Guidance CTS

From Wikicap - European Commission

Technical Guidance for the On-The-Spot Checks (OTSC) and area measurement according to Art. 24, 25, 26, 27, 30, 31, 34, 35, 36, 37, 38, 39, 40, 41 of Regulation (EU) No 809/2014 as amended by Regulation (EU) 2018/746



This webpages, which have been prepared by the European Commission (Joint Research Centre, JRC) in close collaboration with DG AGRI, describe the Commission technical guidelines for the campaign of the On-The-Spot Checks (OTSC). Member States may use these guidelines as Common Technical Specifications of the Invitation To Tender (ITT) published by Member States requiring an external remote sensing contractor.

It aims to describe the technical tasks that the Administrations of the Member States are responsible for and for which some parts may be entrusted to contractors. For the sake of completeness, however, the technical context of the work requires some descriptions of the role and responsibilities of both the Administration and the Commission. Some of the technical details may seem exhaustive, but are included to allow Member State Administrations, and possible contractors, the best possible chance to estimate the expected workloads. Furthermore, as a common document, it has to be inclusive of all the possible choices, options and alternatives that are used in the Member States for their On-The-Spot Checks. It provides technical guidance on how to perform On-The-Spot Checks in general. However, since the majority of the European Union Member States is using Remote Sensing to control at least a part of the subsidies for the agricultural areas funded by the EAGF and EAFRD, most of the information provided concern the implementation of the so-called “Control with Remote Sensing” (CwRS). It has to be complemented by a separate compulsory “National Addendum”, which describes the choices and alternatives applicable in the respective Member State. The information given in this “National Addendum” must be taken into account in the bidders’ reply to ITT. This is all the more necessary as different schemes coexist in the EU which will be applied with different models and variants. Since these Common Technical Specifications do not take into account all particular situations in the different Member States, derogations from particular rules indicated in this document should be introduced in the National Addendum. The information in these pages is up-to-date with the existing EU regulations that are applicable at the time of writing. It is the MS Administrations and the contractors’ responsibility to be aware of other general or specific regulations applicable in their respective Member States. The role of the Commission in a possible procurement procedure for a contractor to perform OTSC work, is strictly restricted to the technical support required to compile the ITT document. The selection, award and follow-up of any contract following from this open procedure is the sole responsibility of the awarding authority in the respective Member States. While the Commission has attempted to make the information contained in these common technical specifications as accurate as possible, it does not warrant the accuracy of the information contained or embodied in the document. The Commission does not warrant or make any representations as to the accuracy of the information contained in the National Addenda produced by respective Member States. Contracts awarded are the sole responsibility of the awarding Administrations in the respective Member States.


AECC: Agri-environment climate Commitments

AECM: Agri-environment climate measure

ANC: Areas of Natural Constraint

AOI: Area Of Interest

AQL: Acceptance Quality Limit

BPS: Basic Payment Scheme as referred to in Title II of Regulation (EU) No 1307/2013

BUNDLE: panchromatic and multispectral image bands (of an image dataset)

CAPI: Computer Assisted Photo-Interpretation (CwRS)

CART: Classification And Regression Tree

CD: Crop Diversification

CSCDA: Copernicus Space Component Data Access

CwRS: Control with Remote Sensing

CY: Claim Year

DEM: Digital Elevation Model

DOP: Dilution Of Precision

DWH: DataWareHouse

CD: Crop Diversification

EFA: Ecological Focus Area

G4CAP: G4CAP is the Web-based application used to manage the whole campaign workflow

GAEC: Good Agricultural and Environmental Condition

GNSS: Global Navigation Satellite System

GSD: Ground Sample Distance

GSM: Global System for Mobile Communications

HDOP: Horizontal Dilution Of Precision

HHR: High High Resolution sensors (enhanced spatial resolution compared to HR)

HR: High Resolution sensors

J(e)PG: Joint Photographic Expert Group

LPIS: Land Parcel Identification System

MEA: Maximum Eligible Area

MS: Member States

MSP: Multi spectral GI raster

OTSC: On-The-Spot Checks

PA: Paying Agency

PAN: Panchromatic GI raster

PDOP: Position Dilution of Precision

PG: Permanent Grassland as referred to in Art. 4 of Regulation (EU) No 1307/2013

PG-ELP: Permanent Grassland under Established Local Practices

RA: Risk Analysis

RAnF: Ratio of Area not Found

RF: Risk Factor

RFV: Rapid Field Visit

RMSE: Root Mean Square Error

RP: Reference Parcel

RPAS: Remotely Piloted Aircraft Systems (drone)

RS: Remote Sensing

SAPS: Single Area Payment Scheme as referred to in Title III of Regulation (EU) 1307/2013

SAR: Synthetic Aperture Radar

SF: Shape Factor

SFS: Small Farmer Scheme as referred to in Title IV of Regulation (EU) 1307/2013

SMR: Statutory Management Requirement

TI(F)F: Tagged Image File Format

UAV: Unmanned Aerial Vehicle (See RPAS)

VCS: Voluntary Coupled Support

VHR: Very High Resolution sensors

VHR+: Enhanced characteristics compared to Very High Resolution

YFS: Young Farmer Scheme


The overall process of OTSC is provided in figure 1 following a chronological approach. The different steps will constitute the chapters of the current page. A general timing and responsibilities for the different steps of CwRS campaign is also provided in table below.

CTS Overview.png

Member State administrations have to define their OTSC strategies and methods in such a way as to ensure effective verification of the correctness and completeness of the information provided in the aid applications and to ensure compliance with eligibility criteria and other obligations (Article 24 of Regulation (EU) 809/2014). To do so, administrations are advised to reflect on, not being an exhaustive list, the geophysical/landscape particularities of the country, the different farm typologies, the staff and budget availability, the typologies of the different payment schemes, etc. Farmers are required to submit their annual subsidy applications in prescribed form and by dates set in line with the Regulation. A sample of the whole population concerned by each payment scheme has to be controlled On-The-Spot. The check of the selected applications can be based on farm visit, or on satellite or aerial remote sensing data, or on a combination of these methods. Part of the OTSC work can be done through the use of external contractors. Prior to the actual performance of checks, it is necessary to ensure a crucial step of data and tools collection and preparation. Then the real work of OTSC of selected applications can take place. When using Ortho imagery (CwRS), each agricultural parcel will be categorized separately by applying the decision tables established by the Administrations to reflect the diagnosis concerning the area, the land use, the land cover, the GAEC, and the Rural Development measures according to the decisions of the Member State. The photo-interpretation of agricultural parcels will normally be carried out using at least one very high resolution (VHR) image - aerial orthophoto or satellite ortho-image with a pixel size <=0.75m (preferably <=0.50m if dealing with small Landscape features) - of the current year to allow the area check of agricultural parcels. Their land use, wherever necessary, will be checked with the addition of a second VHR image but preferably with a set of multi-temporal high resolution (HR) images. The latter can be Sentinel2, HR or HHR. Sentinel1 data (SAR) can also be used. Attention should be paid to the fact that SAR (Synthetic Aperture Radar) data processing requires skills and knowledge different from optical. Please refer to the dedicated chapter in the technical guidance for OTS check of Crop Diversification. In the case where the diagnosis may not be completed by Computer-Aided Photo-Interpretation (CAPI) procedures alone, the contractor or the Administration should trigger a follow-up action for checking the land use and/or some other issues. It has usually consisted in carrying out "rapid field visits" (RFV) if no other evidence available. However, administrations should also consider the possibility to use alternative solutions to capture data and/or gather evidences for the management and completion of dossiers such as the use of geotagged photos or RPAS (drones). Administrations may also opt for the use of only one VHR image to check areas and perform a field visit to check the land use and/or some other issues on all selected parcels (so-called: Systematic Rapid field visit). Following the parcel checks, dossiers will be categorised at payment group level and then at dossier level. Unless specified otherwise, the contractor will participate only in the stages related to the analysis of the remote sensing imagery completing the diagnosis. The penalty calculations, sanctions or financial consequences for the farmer are the responsibility of the Administration. For each dossier inspected OTS, a report has to be produced to document all steps, findings and results. Attention should be paid to any finding that could trigger an Land Parcel Identification System (LPIS) update. At the end of each OTSC campaign, it is highly recommended to perform a work of analysis of the results of the campaign. That consists in doing: a Quality Check (internal and/or external) of OTSC work (both field and CwRS) by re-performing the checks of a set of dossiers; an analysis of the error rates obtained and the main causes that led to these errors. Lessons learned should be capitalised to fine-tune, update if not upgrade OTSC methods for the following OTSC campaign. The Commission’s contribution to the OTSC programme is restricted to the technical coordination of methodological choices and the provision of satellite imagery for control zones defined by the Member State. Since 2007, the quality control procedure is the responsibility of the Member States. The JRC offers the possibility to support Member States in performing a QC of CwRS work on one (or two) CwRS zone(s).

CTS mainstages.PNG

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Documentation, justification and decision sharing

The implementation of the CAP legislation is almost entirely the full responsibility of Member State administrations. Indeed, following the last CAP reform, more responsibility than ever has been given to Member States for the definition and/or decision of many components of the CAP system (e.g. minimum farming activity, list of EFAs, list of GAECs, and definition of a tree …). When a Member State is audited (DG AGRI audit services, European Court of Auditors, etc.) the main aim of auditors’ work is to check that the management and control system set by the Member States is reliable and effective (i.e. ensuring a minimum level of residual error and at the same time meeting the policy objectives). Different solutions may be considered to set a method, and many elements of the IACS may lead to weaknesses in the system.

So, administrations are recommended to document, justify and provide evidence as to their different choices, decisions and actions. It is also very crucial that procedures decided, and decisions and rules set, are very widely shared between all IACS stakeholders: Administration, controllers, farmers (and Commission on request).

Commission guidance, technical guidance and WikiCAP webpages can obviously be used for that purpose. However, it is again recommended to develop and make use in each Member States of solutions like:

- Dedicated Website providing all information on the IACS;
- Webpages dedicated to FAQ (frequent Asked Questions);
- Production of thematic Leaflets or booklets (the application system, the different payment schemes, the EFA list, definition and rules, The GAEC list definition and rules …);
- Production of “Controller guide”;
- Organisation of trainings and/or information days;
- Use of Farm Advisory Service.

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Campaign preparatory work

Define strategy

Member State administrations have the entire responsibility and a large autonomy to define their OTSC strategy. Strategies and methods should be set with the sole aim to ensure effective management and verification of the correctness and completeness of the information provided in the farmers’ aid applications. More precisely, it shall be made to ensure effective verification of (a) the correctness and completeness of the information provided in the aid application, application for support, payment claim or other declaration; (b) compliance with all eligibility criteria, commitments and other obligations for the aid scheme and/or support measure concerned, the terms under which aid and/or support or exemption from obligations are granted; (c) the requirements and standards relevant for cross-compliance […]. This translates into ensuring the effective verification of a particular claim by selecting the most appropriate control method: a classical on-the-spot check or a control with remote sensing (CwRS) or a mix of the two. In practice, this could be done, after carrying out a sample selection on the level of the individual claim, by looking at the clustering and / or location of parcels and thereafter choosing the appropriate control method.

In financial term, an effective administration and control system should lead to an overall error rate below a materiality threshold of 2 % (European Court of Auditors criterion).

There is NO ONE single OTSC strategy fitting all farmland situations in Europe. The definition of sound strategies requires a good knowledge and analysis of the Member State and/or Regions farm structure and farmland characteristics. To do so, administrations should make use of GIS technologies. Different layers and data set (e.g. LPIS layer, EFA layer, digital applications, road network layer …) could be combined and queried to help optimising field checks organisation, defining CwRS strategies, performing risk analyses, and optimising CwRS imagery use.

In addition, administrations can make use of the different results and findings of Quality Checks (see dedicated chapter), the LPIS Quality Assessment (see LPIS QA WikiCAP pages), or even the residual errors to adapt and fine-tune their control strategies.

Sample selection

On the 1st of January 2015 entered into force a new system of selection of the samples to be OTS checked for the different payment schemes (BPS/SAPS, Greening, VCS, SFS ...) and policy measures (Cross Compliance, Rural Development measures …). Selections are now mainly random based. Some elements (e.g. ‘Greening’, Cross compliance …) also include a risk based part. Note that as from the 1st of January 2018, the Reg. 809/2014 has been amended. The 'cascade system' in place has been deleted and replaced by new sampling requirements.

Random selection

The random sample permits an estimate of the background level of anomalies in the system. It supports decisions enacting the mechanism for increasing the control rate (in accordance with Art.35 of Regulation (EU) No 809/2014) and also permits an assessment of the effectiveness of the criteria being applied for risk analysis. There are several types of random samples, as well as different methods for compiling the random samples. For more details, please refer to section 1.3.2 of document DSCG-2014-32-FINAL_REV4.

Risk Analysis and annual assessment

According to Art. 34(5) of Regulation (EU) No 809/2014, MS are responsible for the definition of the risk criteria to be used for the risk analysis. It is the MS' responsibility to assess the effectiveness of the risk analysis on an annual basis and to update it by establishing the relevance of each risk factor. For further details, refer to section 1.4 of DSCG-2014-32-FINAL_REV4. The risk factors can be qualitative (e.g. region/district/department …) or quantitative (e.g. area declared, ratio of crops, EFA declared, number of participating schemes…). It is worth noting that risk factors might be different among schemes and/or among the MS. The only constraint is that each risk factor must be known for each beneficiary in order to assess his/her own risk. Depending on the scheme, several variables are influencing both the reductions and the penalties systems. However, for area related subsidies and for ‘greening’ measures, the ratio of “area not found” (RAnF),) i.e. the total area not determined in the relevant crop group/EFA over the total declared area for the same crop group/EFA, is a common parameter. For the crop diversification (CD) in the ‘greening’, the other parameters are the declared shares of each crop within declared arable land. For this, MS can use a CART model (i.e. Classification and Regression Tree) with the area not found in individual claims as the dependent variable (i.e. the variable to be predicted). The CART model relies on a set of independent variables (i.e. the explaining variables; here, the potential risk factors) in order to find homogeneous sub-groups of the population (called the “nodes”). Advantages of the CART model are that it is:

- Well implemented in various statistical software (e.g. Matlab, R, S+, …);
- Relatively easy to apply (it only requires the input of the dependent variable and the potential risk factors);
- Flexible (no assumption is made how the potential risk factors are affecting the dependent variable);
- And irrelevant risk factors are automatically excluded from the model.

When calibrating the model, attention must be paid to the maximum level of the tree (i.e. maximum number of consecutive nodes) and the minimum number of observations in a node (generally at least 50). After calibrating the model, a procedure named “pruning” is applied in order to remove the minor nodes in the tree. Ideally, the procedure is sequentially repeated to get simpler and simpler models. The final model is then chosen by optimizing criteria (e.g. minimum predicted variance on the validation set). If possible, the validation set should be independent from the calibration set (i.e. the individual claims that were used for the calibration should not be used for the validation). Using the final CART model, it is possible to estimate the RAnF for each application and thus to estimate the discrepancy between the claimed area and the paid area (i.e. after deduction of the reductions and the penalties). These estimations on the whole population of beneficiaries can be used within the following alternative procedures:

- set a threshold determining the “low” and “high” risk sub-population, then select randomly within the “high” risk sub-population;
- as proxy for a probability-proportional-to-size sampling of the applications (ensuring thus to sample mainly the larger expected errors;
- regroup the applications with similar estimated risk (e.g. classes of discrepancy between claim and payment). A stratified random sampling can then be applied on these strata with a sample rate per stratum determined by the total risk of the corresponding stratum.

For instance, in the third alternative, a risk stratum that covers 30% of the total risk of the population (i.e. the sum of the estimated risk within this stratum is equal to 30% of the total sum of estimated risk) should represent 30% of the total sample size even if they are composed of only 10% of the total population. Knowing this sample size for the stratum, we can then translate it into a sample rate for the stratum. Thus, if the total population is 100k claims, the risk stratum above should be sampled as follows:

CTS riskanalysis.PNG

In the example, column (e) is computed as 4% x 100k x (d) (e.g. the first row is 4% x 100k x 40% = 1.6k), 4% being the objective risk-based sample rate (in the case of the population exempted from greening, the risk-based sample rate is 2.4%). That is the number of claims that must be selected in the stratum and put in the risk-based sample while column (f) is computed as (e)/(a) (e.g., for the first row is 1.6k/5k = 32%) and is the percentage of claims within this stratum that must be selected.

CTS comp riskanalysis.PNG

Selection of control zones

Contrary to classical checks, which can be individually geographically dispersed, in the case of CwRS, the areas where imagery is to be acquired need to be established. This clustering of checks is called a "control zone" with a geographical area defined on the basis of GIS analysis. It is worth noting that classical checks can also be organized in geographical clusters. The following descriptions can thus be arranged for any combination of classical checks and/or CwRS. Despite the clusters, it is essential to ensure the representativeness of all conditions/ requirements of the targeted schemes and measures in the choice of the RS zones (see in particular Art. 34(2) last sub-paragraph of Regulation (EU) No 809/2014). This is particularly true as RA is mainly foreseen to be used for the greening samples. As a basis, the Commission services recommend opting for a high number of zones of small size. However, this recommendation needs to be reassessed by taking into account the regional conditions within each MS. The optimal combination of number and size of zones is highly dependent both on the spatial extent and spatial integration of the farms in the landscape.

- The spatial extent is influenced by the size of the farms and the distances between the agricultural parcels of each farm;
- The spatial integration of the farms in the landscape is characterized by the spatial overlap of the farm extents.

The figure hereafter illustrates 4 possible scenarios summarizing the different combinations of spatial extent and spatial integration of the farms. Clearly, for the same number of controlled farms, a landscape characterized by large spatial farm extents with small overlaps will require larger images than a landscape characterized by small spatial farm extents with high overlaps.

CTS Farm struct.png

Influence of the farm spatial structure and integration on the required image size for CwRS.

It is reminded that the location of the zones shall remain confidential. In case of the use of contractor, zones should not be disclosed until a contract has been awarded. The RS zone can be selected randomly and on the basis on a risk analysis. The selection possibilities are detailed in section 1.5 of document DSCG-2014-32-FINAL_REV4.

- For the selection of dossiers

For the selection of dossiers, and especially for zones to be checked with satellite images to be acquired on Commission budget, attention as to be paid to the cost/benefit of such imagery.

For instance, even if no thresholds are currently imposed by the Commission (i.e. no min and max number of dossiers per zone), it is recommended to look for the optimisation of parameters like the total area of applications to be checked inside the total Area of Interest (AoI) of images. For areas with very few dossiers, classical OTSC should be preferred.

- In case of contractor

After the phase of samples selection, approximate figures on the number of dossiers and zones should be given in the National Addendum. The approximate size of the zones should also be given by the Administration to the bidders. These figures, that should be taken as provisional, are intended to help the bidders assessing their workload. Also, in order to help the bidders determining a mean cost per application, the Administration should indicate the mean number of parcels per application and per zone, if requested by the bidders, as this number may vary significantly between regions of a given Member State.

Suggestion of an iterative procedure for the selection of zones and samples

DG JRC suggests to rely on the following procedure for the selection of both the control zones and the different OTS samples (random and risk). The procedure can be applied for any combination of classical checks and/or CwRS. In the description of the procedure, it is assumed that the RAs have already been conducted so that the risk associated to each individual beneficiary can be evaluated. The description is made for the BPS/SAPS population but can be translated to other schemes (e.g. second pillar). Step 1: Anticipate the estimate of the required number of controls for each considered schemes accordingly with the beneficiary population. For instance, the share of the initial random selection is 20% (1% out of 5% of the controls), while the expected share (noted Sg% hereafter) of the ‘greening’ risk-based sample is the ratio between the number of risk-based ‘greening’ sample on the total number of controls (i.e. 5% of the population); Step 2: Select randomly a control zone; Step 3: Apply the sampling on the zone using the expected shares computed in Step 1. In principle, all the beneficiaries of the control zone could be selected for controls in any of the different schemes. By doing so, the cost efficiency is guaranteed. However, this is not mandatory and the beneficiaries that remain non selected can be put in a reserve list for completing the sample at a latest stage; Step 4: Add the different samples to the samples already selected on the previous control zones and check whether the target sample sizes are reached; Step 5: If all the target sample sizes are reached, stop the procedure.

Otherwise, repeat Steps 2 to 4 until all sampling targets are met.

In addition, it is recommended to:

- Consider to pre-select a slightly larger sample in order to guarantee that the target sample size will be reached;
- Make the pre-selection estimation on slightly smaller zones than the final zones to increase the chances that the beneficiaries can be controlled (especially when using CwRS);
- Consider the possibility to switch from CwRS to classical checks if the control zone covers only few beneficiaries;
- Consider to select the last control zones in accordance with your needs. For instance, if the risk-based ‘greening’ sample is under represented, you might want to select the last control zone(s) by RA.

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Preparation of checks

In order to check the conditions under which an aid is granted it is crucial to ensure a complete step of tools preparation and data gathering, pre-processing and processing.

Reception of applications and data entry

From 2018 onwards, all farmers have to provide information for their aid applications and payment claims, via a GIS-based interface (the geo-spatial aid application - GSAA). See guidance document on aid applications DSCG/2014/39 FINAL-Rev3. In view of facilitating the submission by the beneficiaries and to reduce the risk of errors, Member States shall provide pre-established digital forms. Through these forms, it is advised to provide as much information as considered useful based on diagnoses and checks made on parcels in the previous year as well as any relevant recent ancillary graphic material. Furthermore, to limit errors, it is recommended to avoid to require free text information. Farmers should provide information via drop-down menus or tick box lists using pre-defined common options and nomenclatures. If an administration makes use of a contractor, the applications will be transmitted to the contractors in digital form, after having been subjected to consistency checks, and possibly under an anonymous form. The format of the database given to the contractor will be described by the Administration, and accompanied by a list of the codes to be used.

Collection of LPIS data and other ancillary documents

Access has to be prepared and made available to the controllers for the relevant parts of the LPIS and EFA layers (i.e. the reference vectors, as well as the reference areas) and if any, the associated orthoimages. The applications to be controlled should contain appropriate cartographic documents allowing to locate all agricultural parcels, and, if applicable, all required EFA elements on the ortho-images or inside reference parcels.

Provision of satellite images

Since 1993, DG AGRI has promoted the use of “Controls with Remote Sensing” (CwRS) as an appropriate control system suitable to check if aids are correctly granted. Following the Council Regulation (EC) 1306/2013and of the Commission Implementation Regulation (EC) 809/2014, 908/2014, the Commission Services are required to centralize the Satellite Remote Sensing (SRS) image acquisition. This task was transferred to DG JRC in 1998 (September 1998/VI/34942) and it is managed through a horizontal co-delegation (Type I) between DG AGRI/DG JRC (via DG BUDG) to implement the yearly CAP image acquisition work programme.

Concerning the timing of the operations, article 26 of the Commission Implementing Regulation (EU) No 908/2014 states that:

1.) For the purposes of Article 21 of Regulation (EU) No 1306/2013, each Member State shall inform the Commission by 1 November of each year at the latest, as to:
(a) whether it wishes the Commission to acquire the satellite images necessary for its programme of checks and/or for its Land Parcel Identification System Quality Assessment;
(b) the area to be checked and the number of planned control zones.
2.) Member States requesting the Commission to obtain the satellite images shall finalise, in cooperation with the latter and before 15 January following the communication of information referred to paragraph 1, the zones to be covered and the timetable for obtaining those images

With reference to Table 1 of Chapter 1, MS Administrations shall insert at first their pre-Image Requirements (pre-IR), and then the final detailed image requests in the web application G4CAP in accordance with above deadlines. For details on the web application G4CAP used to synchronise all stakeholders in the satellite image acquisitions for the CAP please refer to G4CAP . One has to note that:

1.) For all interactions, user/pwd (credentials) will be requested to and assigned by JRC;
2.) and manuals can be found under ‘Documentation’ menu and no credentials are needed.

Management of satellite image acquisition

All instructions valid for the stakeholders (or Actors) participating in the CAP image acquisition: DG AGRI, DG JRC, MS Administrations, MS Administrations’ contractors, FW contractor/s (with their two roles: operator and image provider) are given in image specifications for the CAP checks which are updated every campaign. These specifications are divided into the VHR, VHRplus (or VHR+, of enhanced quality) specifications, and the HR and HHR specifications. The specifications details are available on the G4CAP website. The image acquisition process described follows the hereafter workflow together with the colour legend of responsible actors.

The satellite image acquisition process with relevant responsible actors

Use of COPERNICUS datasets

The MS Administrations and their contractors can make use of the Copernicus infrastructure sensors Sentinel1 (SAR) and Sentinel2 (optical), and its DataWareHouse (DWH) datasets.

The Sentinel datasets are free of charge and openly accessible. The EC strongly encourages using all cloud free S2 images wherever useful in their CAP controls. Sentinel 2 (A and B) satellites have a wide swath width and high revisit time (10 days at the equator with one satellite, and 5 days with 2 satellites (2A and 2B) under cloud-free conditions which results in 2-3 days at mid-latitudes. (i.e. up to 12 passes per ‘normal’ length CwRS window). It is up to the MS Administrations to download S2 data from ESA or elsewhere. The DWH datasets follow a licensing agreement that may allow download (DL), or VIEW, freely for Public Authorities, after registration to the Copernicus Space Component Data Access (CSCDA). These DWH datasets include a vast number of CORE and ADDITIONAL datasets, including pan EU HR and VHR coverages which are renewed every 3 years, and can be used most suitably in preparatory work for the CAP controls. Also, the EC strongly encourages using Sentinel1 data as part of the CAP checks process. However, since S1 A and B are all-weather, day-and-night radar imaging satellite, data availability (also here 3-4 days revisit time) over a specific CwRS zone is known and there is no need for an ‘alerting system’.

Acquisition of aerial imagery (if applicable)

Acquisition of aerial imagery for the checks is the responsibility of the MS Administration, i.e. it is not coordinated by the Commission. The main advantage of aerial imagery with respect to VHR satellite imagery is that it allows covering much larger areas (e.g. large administrative units such as full provinces) in a relatively limited period of time. Alternatively, a large number of small zones may also be covered in a given region. However, acquiring aerial imagery has also some proper constraints such as restrictions over military zones and air traffic lanes. Cloud cover is not as restricting for aerial photography as for satellite imagery, but meteorological conditions are in any case affecting the radiometric quality of the images. Moreover, the lead-time in the acquisition-processing of aerial imagery may be longer than that for satellite images. Aerial images acquisition must therefore be organised sufficiently in advance, and the acquisition periods should be relatively early in the year. The use of (natural colour in combination false colour composite) imagery permits an easier identification of land covers, thus significantly reducing follow-up rapid field visits for crop identification.

It is also compulsory that aerial flights be carried out within the present state of the art: the use of GNSS and inertial navigation systems linked to the camera makes it possible to optimise the flight coverage and considerably reduce the costs of further processing.

If Administrations and/or contractors intend to acquire and/or ortho-rectify aerial digital imagery, they should refer to the Best Practice and Quality Checking of Ortho Imagery JRC guidelines G4CAP (under Documentations menu).

To safeguard EU funds and since aerial image acquisitions are not coordinated by the Commission, it is the responsibility of the MS administrations to avoid a situation of acquisition of VHR satellite imagery contemporaneously to an aerial acquisition.

Processing of imagery

The person in charge of image processing should record and substantiate all steps and all processing techniques used: geometric ortho correction, radiometric correction, contrast stretching, resampling, pan sharpening, mosaicking.

Geometric correction

The Commission does not impose a methodology for geometric correction of imagery, but gives recommendations and guidelines in line with its Quality Assurance (QA) strategy described in the Guidelines for Best Practice and Quality Checking of Ortho Imagery. The purpose is to have a set of suitable procedures to ensure a satisfactory quality of the product. These guidelines are to be considered as the Commission’s current understanding of “best-practice”. It must be clear, however, that in the end the administration/contractor alone is responsible for the accuracy of products. The entity in charge of image processing needs to have appropriate software suite (or sub-contracting options), and “know how” to process all image types (i.e. be able to ortho-rectify all image types, pan-sharpen bundle images, etc.). The allowed geometric error in the output images (and associated Digital Elevation Models, DEM) are expressed as a maximum permissible absolute (i.e. with respect to a specific geodetic reference frame) Root Mean Square Error (RMSE) with respect to well-defined and independent check points, and are stated in the Technical Specifications mentioned above. The geometrically corrected products and associated DEMs are assessed separately in three geometric dimensions i.e. RMSEx, RMSEy, and (where relevant) RMSEz. Since 2014, the EC has introduced the use of so-called VHR, HR and, more recently, HHR image profiles. Examples are VHR prime, VHR topographic, VHR LPIS (special case), VHR pan, VHR stereo, VHR archive, or even VHR backup. These are sensor independent profiles, fitting the CAP VHR, HHR and HR image specifications in terms of spatial resolution, radiometric resolution, number of spectral bands, geolocation accuracy/absolute geometric accuracy achievable in orthorectification, elevation angle, programming type, processing levels, and cloud cover threshold over the control zone (AOI) etc. The profiles are showed in the VHR/HR Image Acquisition specifications. It is essential that the MS Administrations or their contractor conform to these guidance. Below figure shows a summary of the VHR and HR profiles.


VHR/VHR+ profiles adopted within the CAP checks

HR/HHR profiles adopted within the CAP checks

In order to meet these specifications, the person in charge should carefully analyse the input data and particularly the Digital Elevation Model (DEM) to be used, the ground reference data (accuracy of Ground Control Points (GCP), independent checkpoints (ICP) used, their source, number and distribution) and each step of the geometric correction process. One should record all steps of this geometric correction process, and justify the correction method used (e.g. ortho-correction or polynomial) for the control zones.

By Digital Elevation Model (DEM) it is intended a regularly-spaced raster grid, representing the elevation of land surface, referenced to a common vertical datum (usually the sea level). The artificial built-up (powerlines, buildings and towers) and natural (trees and other types of vegetation) features are voided and are not extruded in a DEM. Thus, it typically represents the bare, ground surface of the earth. This has to be distinguished from a Digital Surface Model (DSM) that captures and depicts the natural and built features on the Earth’s surface (often costly to create using LIDAR system). In some countries, Digital Terrain Model (DTM) will be used as a synonymous of DEM. However, in many other countries DTM has a slight different meaning. In the context of the CwRS, DTM is a vector data set composed of regularly spaced points and natural terrain features such as ridges and breaklines. A DTM represents land surface much better than DEM. Obviously, from these regularly-spaced points and breaklines, a DTM can be rasterized (gridded) into a DEM. Such augmented DEM, if available, would be the one recommended to use to produce the most accurate Ortho-rectified VHR imagery.

Radiometric correction

Imagery checks, especially those conducted for the LPIS QA screening, revealed that the quality measures related to radiometry and photometry given in the JRC ortho-guidelines and specification for ortho-imagery needed some further clarification. Details are provided Radiom_Correct.

Ground data collection

As a support for the CAPI and/or as training set for classification of the satellite images, it is recommended to build a database of reference fields for the most common land use/crops in control zones. The survey(s) have to be carried out at the beginning of period(s) most appropriate for the crops of interest (winter crops, summer crops, secondary crops, permanent crops, grassland management …). Surveys should ensure a good representation of the main land use/crops (for example 5 to 10 parcels per land use/crop type spread over control zones) and include, if applicable, some examples of infrequent land use/crops.

Production of a Controller guide (field check and CAPI)

One of the main elements influencing the accuracy of On-The-Spot checks results is the use of appropriate tools and the use of tools appropriately. Likewise, is the consistency of the defined rules to identify, delineate and measure features and crops of interest for the different CAP schemes.

The production of a controller guide is thus crucial to document and share the defined rules among the different stakeholders (at least CAP administrators, controllers, and farmers).

In this guide, attention should be paid to the provision of clear feature specific identification rules applicable both on imagery and on the field. The basic assumption is that a specific feature on the ground remains obviously the same feature on imagery; thus, its delineation and/or measurement should come with the same result whether it is checked using imagery or in the field.

The guide should contain drawings and example pictures to illustrate specific cases, it should further provide information on possible ancillary data (archive imagery, river, transport networks etc.) that could help identifying and delineating features. The guide should also contain the common praxis on how and what to report for the parcels and dossier under check.

GNSS devices and ortho image validation

The use of tools - whether ground or remote sensing based - for the measurement of agricultural parcel areas requires that all interested parties can expect reliable and trustable measurements.

The JRC has developed and proposed a method for the validation of tools for area measurement, which can objectively assess the correct performance (under specified conditions) and attest therefore that the tool fits for the purpose of parcel area measurements made in the context of field checks required in Commission Regulation.

While not mandatory, it is highly recommended to Member States to validate their measurement tools through the JRC method. Alternatively, Member States can also:

- use a device tested and certified by an authorized entity;
- use a device tested and validated by a reference laboratory approved by JRC.

The full description of the JRC "Area measurement tool validation method" is provided Valid_Method.

Lastly, while a tool is not yet validated, a buffer tolerance of max. 0.5m can be applied for GNSS based measurements. For area measurement on cartographic materials (digital) it is broadly accepted that the buffer tolerance is equivalent to 1.5 * pixel size (so-called rule of thumb).

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Perform checks

The purpose of on-the-spot checks is to check the conditions under which aid is granted in accordance with Article 37 of Regulation (EU) No 809/2014. In summary, this means to check for each parcel declared: their location, area related aspects and land use/land cover related aspects. Diagnoses will be attributed at parcel level. When using imagery, in case of non-conclusive opinion on a parcel, a Rapid Field Visit (RFV), or other follow-up (e.g. geotagged photo), shall be undertaken for completion of the diagnosis at parcel level. Then, diagnoses at parcels level will be aggregated to provide a diagnosis at crop group and/or payment scheme level. Finally, a diagnosis will be provided at dossier level. As a by-product of these checks, feedbacks to the LPIS should be made (e.g. using specific codes) wherever appropriate.

Checks at parcel level

Definition of the agricultural parcel

Art.67 of Regulation (EU) No 1306/2013 defines the agricultural parcel in the following way: “agricultural parcel” means a continuous area of land, declared by one farmer, which does not cover more than one single crop group; however, where a separate declaration of the use of an area within a crop group is required in the context of Regulation (EU) No 1307/2013, that specific use shall if necessary further limit the agricultural parcel; Member States may lay down additional criteria for further delimitation of an agricultural parcel; When a Member State opts for further limitation of the agricultural parcel, the same definition should be applied systematically.

General principle

While taking account of the definition of crop group of Art.17 of Regulation (EU) No 640/2014, Member States have the possibility to choose the most appropriate "level" of the agricultural parcel for their context: it could for instance be the "BPS/SAPS crop group" parcel as shown in the example below which should be further delimited in case of area-related VCS.


It could also be the agricultural area type of parcels (arable land, permanent grassland/ permanent pasture, permanent crop) as shown in the example below.


Where the Member State defines the "single crop" parcel as the agricultural parcel, the four fields in the example below would correspond to four agricultural parcels (one of these, being also claimed for VCS).


Where the crop or cover type is not explicitly required by the regulation as an eligibility criteria for the payment, declaring "crop group" parcels instead of "single crop" parcels may simplify the farmer's declaration and the control, in particular when a "crop group" parcel is composed of one or more fully declared reference parcels. However, in case of a VCS based on a certain crop, the agricultural parcel shall be set at the level of this single crop and the minimum parcel size defined by MS applies.

Sample of parcels to be determined/measured

As a principle, on-the-spot checks shall cover all the agricultural parcels for which an application for aid has been submitted and the check of their eligibility conditions and where appropriate uses, in relation to each scheme should be carried out. However, as introduced in 2018 through the amendement of Art.38(1) of Regulation (EU) No 809/2014, the actual area measurement including the eligibility check of the agricultural parcel as part of an on- the-spot check may be limited to a randomly selected sample of at least 50 % of the agricultural parcels for which an aid application and/or payment claim has been submitted under the area-related aid schemes and/or rural development measures. When this sample check reveals any non-compliance, all agricultural parcels shall be measured and be subject to eligibility checks, or conclusions from the sample shall be extrapolated. In other words, to ensure a correct determination of the reduction of the aids and administrative penalties, either the sample randomly selected is extended to include all the remaining parcels of the aid scheme(s) concerned or the difference found on these parcels shall be extrapolated to all parcels relevant to the aid scheme(s). In order to improve the efficiency of the control, parcels declared in other applications sharing a reference parcel with any application from the control sample may be included. This recommendation is valid for any type of on-the-spot check (classical control or CwRS), and particularly for checking joint cultivation. Such "ancillary" applications are likely to be incomplete and should not be completed in the field and do thus not count towards the on-the spot check control sample. However, although very partially checked, these applications could lead to a reduced payment and administrative penalties on the basis of irregularities found on the parcels checked.

Parcels, once selected, should not be dropped from the set to be checked. As regard crop diversification, where the MS has not chosen the "single crop parcel" as the agricultural parcel, the OTSC should ensure a sufficient level of determination/measurement of the areas of each single crop declared (including land laying fallow and grasses or other herbaceous forage). This could be done e.g.:

- by systematically determining/measuring, within the "50% agricultural parcels sample", the "single crop areas" declared and where necessary, determine/measure additional "single crop areas" until the crop diversification requirement is verified as fulfilled (i.e. in case of at least 2 crops required, verification of "at least 25% of the arable land covered by second crop and others" and in case of at least 3 crops required, verification of "at least 25% of the arable land covered by second crops and others" and "at least 5% of the arable land covered by third crops and others");
- by applying the same rule of sampling of Art. 38(1) at the level of "single crop areas" (in addition to the application of Art. 38(1) at the level of the agricultural parcel).

Where a beneficiary declared the details of the only crops demonstrating that s/he is exempting from crop diversification, it is recommended to determine/measure all those relevant "single crop areas" to check the exemption. Where use is made of RS, it must be ensured that the parcels outside the zone have an equal chance of being selected when the derogation of limiting the control to at least 50% of parcels is applied, even if all parcels inside the zone represent more than 50% of agricultural parcels for which an application has been submitted and the control result inside the zone is satisfactory. Otherwise there is a risk of introducing a bias in the sample.

Parcel location

In the field, at least the farmer’s sketch map provided through the Geo Spatial Aid Application (GSAA) have to be provided to the staff in charge of the checks in order to correctly locate any single parcel. Alternatively, navigation systems based on GNSS and systems allowing the display of images, vectors and data on a mobile computer/tablet in the field may be used to locate and reach the parcel of interest. On imagery, each declared parcel will be located on screen with the help of the LPIS vectors layers (reference parcels, landscape features, EFAs ...) and the farmer’s sketch map provided through the Geo Spatial Aid Application (GSAA).

It is important to locate and delineate all declared parcels, including those for which no aid is claimed, to detect possible multiple claims and to verify cross compliance issues.

Area check

The inspector should have received sufficient instructions and training, and be able to undertake the work autonomously. The inspector should have no conflicts of interest, and should be able to carry out the inspection independently. In order to provide a result to the appropriate precision and to ensure effective verification, the inspector must have access to appropriate claim data (including map information) and data collection/measuring equipment. Also, as a general rule, the area of each subsidised agricultural parcel will be verified either on the field or on the current year VHR imagery (i.e. <= 0.75m pixel size). Unless requested otherwise by the Administration, the area of non-subsidised agricultural parcels will, in general, not be checked.

The result of the digitisation or field measurement will be the “measured” area, which will be compared to the “declared” area of the corresponding parcel. The results will be expressed as the area projected in the national system used for the LPIS and in hectares rounded to two decimal places.

Attention should be paid to the definition of the agricultural parcel attached to the crop group or payment scheme under check. The inspector/controller shall follow this definition when measuring parcels (see ‘definition of agricultural parcel’ chapter of DSCG-2014-32-FINAL_REV4).

The total area of the agricultural parcel should be measured. However, areas not taken up by agricultural activities such as buildings, woods, rocks, some ponds and paths are to be excluded by deduction from this area (it is reminded that these measurements and exclusions have to be done without applying any tolerance since there is no reference or declared area value for these elements to be compared with).

To assess the eligibility of areas within an agricultural parcel of permanent grasslands, Member States can use a reduction coefficient (please refer to the Technical guidance on the pro rata system for permanent grassland). Member States shall define beforehand the criteria and procedure used to delimit the (in)eligible part of the parcel in order to ensure that these criteria are communicated to farmers, correctly transposed, where necessary, in the LPIS and adequately included in the instructions for the on-the-spot checks. In the office, on-the-spot checks need to be prepared by selecting the areas to be measured, grouping and/or subdividing the parcels declared with reference to the LPIS, and arranging visit itineraries as efficiently as possible to optimise holdings check time. The direct – preferably in digital form – consultation of the LPIS data (including where applicable orthophotos) shall be possible for the preparation of field controls.

The LPIS data should be available also for use during the on-the-spot checks.

Where features that are part of the good agricultural and environmental condition obligations or the statutory management requirements (e.g. hedges, drainage ditches, small woods according to the local regulations) have been specifically recognised and defined as (landscape) features eligible for area payment, they should not be excluded from area measurement. Nevertheless, it is recommended that, during the on-the-spot checks (i.e. remote sensing or otherwise), the inspector reports the presence of these features in the control file. Some Member States have digitised such features as points, lines or polygons with their corresponding attributes in the LPIS, this way making easier and more effective their management and control of their maintenance. There are two options for measuring the agricultural parcel area: 1) direct measurement or 2) measurement by deduction, which is applicable only in particular circumstances. The measurement by deduction can be done when the Land Parcel Identification System (LPIS), together or not with other ancillary data such as ortho-photos, permits the confirmation of the boundaries of the declared agricultural area. Thus, the area measurement may focus on the determination of ineligible areas and deductions. This situation is only possible when:

- the LPIS reference parcel is an agricultural parcel; or,
- the reference parcel is fully declared; or
- use is made of he GSAA, which allows an overlay of boundaries and eligible area as reported on the image;
- and areas not to be accounted for (deducted) can be easily identified.

In all other circumstances, a direct measurement of the parcel area (e.g. using GNSS or VHR ortho-image) is required. For details on the deduction of ineligible features, please refer to section 3.2.2 of document DSCG-2014-32-FINAL_REV4.

Material to be used for area measurements (and associated tolerance)

MS shall use measurement tools that are proven to assure measurement of quality at least equivalent to that required by applicable technical standard, as drawn up at Community level. In other words, accuracy of measurements must be at least equivalent to the accuracy needed for the management of geo referenced data at cartographic scale of 1/5.000. The quality of a given tool is defined by the tolerance (i.e. buffer width) applicable to this tool as determined through an area measurement validation test.

In concrete terms, only tools (e.g. GNSS equipment, remote sensing ortho-images) with a buffer width not exceeding 1 m should be used.

All information concerning the tool area validation test set by the JRC can be found under the following link "Area measurement tool validation method".

- Use of VHR ortho-imagery

If VHR imagery (i.e. pixel size <=0.75m) is used for parcel area measurement, current image shall be used. Recent archive VHR imagery can be used only if it enhances the interpretation primarly made on current year VHR imagery, therefore helping the interpreter making the decision. It is reminded that VHR imagery should be accurately ortho-rectified (see corresponding section). For the delineation of parcel boundaries, a viewing scale of 1/1.000 would often be suggested. However, the interpreter should vary the viewing scale depending on size and type of parcel to be measured and store this information in the OTSC report. Where reference parcels (LPIS parcels) contain several (full or partial) agricultural parcels, the CAPI operator will have to locate and digitize the declared agricultural parcels inside the LPIS parcels using the sketch maps contained in the farmers GSAA and taking account of the current definition of the agricultural parcel. Since farmers’ sketch maps are only indicative, operators are advised to report cases where the retained area significantly exceeds the declared area so that complementary checks may be carried out by the Administration (particularly for dossiers where the possible excess of the retained area compensates for an under-declaration). Such cases may occur when the operator is not aware of all declared parcels in the reference parcel (e.g. as a result of the sample selection) or because some parcels may not be declared (e.g. because they belong to non-farmers).

It is reminded that VHR ortho imagery should be validated according to the JRC validation test method. In absence of validation, a buffer tolerance default value can be set using the rule of 1.5 times the imagery pixel size (e.g. 75 cm buffer tolerance for a 50 cm pixel size)

- Use of Stand-alone GNSS devices

The GNSS equipment choice offered on the market is very wide, but not all devices meet the accuracy requirements imposed by the Regulation. Nowadays, most of devices come with dedicated packages allowing measuring parcel areas. If an Administration decides to acquire a new GNSS receiver, it is advised to perform an area measurement validation tests to know if it meets the required accuracy.

How to measure the area?

The general method to measure a parcel area consists in following the parcel perimeter with the GNSS device.

It is reminded that it is the GNSS antenna that determines the physical geo-location of the device. So, the antenna should always be positioned and maintained at the vertical of the perimeter to be measured.

The user should be aware of the possible difficulties that may arise during measurement, such as loss of satellite signal, multi-path effect etc. Some of these difficulties can be reduced by an appropriate set up of parameters like: signal to noise ratio (S/N), maximum Position Dilution of Precision (PDOP) and horizon mask.

In any case, a visual check of the parcel recorded should be systematically be done to detect blunder points (see Figure below).

CTS GNSS Loss signal.PNG

Example of an error connected with loss of satellite signal.

More generally, large discrepancies with the declared area should, in case of doubt, always lead to a second measurement.

Whenever the measurements need to be taken in a difficult area like a valley or neighbourhood of a forest, a measurement planning software is advised to be used. This software allows simulating the configuration of the GNSS system at a certain point and time of the day, month, year. As the position of satellites is changing in time, selecting the optimum time of the day for the measurement can help achieving a reliable result in a short time.

CTS Numberof satellite.png

Left: Simulation of number of satellites in the certain position with some obstacles on the side. Right. Simulation of the Horizontal Dilution Of Precision (HDOP) in the certain position with some obstacles on the side.

Some software are also able to take into account the features potentially blocking the signal from the satellites. This is done by introducing a simple sketch of the position of the obstructions influencing the test field in the software. The horizon is therefore reduced according to this sketch, making the simulation more realistic (see herafter.).


A sketch of the situation in the field. A feature blocking signal (in grey) on the west side of the object to measure.

Continuous measurements or logging vertices only?

The appropriate method of measurement as well as advice for optimizing the measurement accuracy are usually suggested by the manufacturer.

Nevertheless, as a general rule, the use of the continuous mode is recommended as it increases the possible compensations between point position errors, thus also for squared or rectangular shape parcels. When elements (e.g. a wood or a hedge) obstruct the passage on the perimeter, it is advised to switch to the stop & go method.

For parcels with very straight borders, one may decide to perform measurements with logging vertices (at each corner) method. However, it often proved not to be faster than the continuous measurement method, since several logging vertices must be recorded by corner. Also, possible compensations between point position errors will be reduced (so increase of possible measured area error) since the number of points will be significantly lower than with a continuous mode measurement.

Please note, that the result of the validation is strictly related to the tested method of measurement and not only to the device.

Therefore, it is strongly recommended to perform the GNSS validation test in both continuous and vertex methods.

An often commented fact is that the tracks of the measurements taken with the continuous measurements method look 'worse' (more noisy) on the screen of the device (and in the GIS) than the ones collected by logging vertices only. The purpose of the on-the-spot controls is to find the actual area eligible for payments and to verify the farmer's declaration in a fair way. Therefore, the reliability of the measurement and the best practice in taking the measurement should be a priority over the 'sharp' shape of the field. In other words, the method of the measurements should be adjusted to the tool and conditions of the measurements rather than to the preferences for seeing 'straight' borders in the GIS database.

- Use of differential GNSS, geodetic survey GNSS receiver or total station

These types of devices are more expensive than standalone GNSS, they require more expertise to use them and require more preparation time to have them up and running. However, these instruments allow to obtain accuracy at centimeter level. They fully fit for purpose for measurements done in the frame of LPIS update.

Such type of instrument has to be used for measurement of Reference Parcels to be then reported in the LPIS.

It is reminded that GNSS should be validated according to the JRC validation test method. In absence of validation, a 50 cm buffer tolerance can be used as default value.

Why a single value buffer tolerance?

For area measurements performed in the frame of On-The-Spot Checks, Member States shall use measurement tools that are “proven to assure measurement of quality at least equivalent to that required by applicable technical standard, as drawn up at Community level”.

As from 1 January 2008, it has been decided that only the perimeter “buffer” tolerance shall be applied to agricultural parcels to express the measurement accuracy of a given tool (e.g. GNSS equipment, ortho-imagery). The buffer tolerance of each specific tool has to be determined through an area measurement validation test (JRC validation method) or through certification.

The validation test is made under artificial/controlled conditions to limit as much as possible ‘external’ error factors (e.g. bad use of instrument, non-respect of parcel border …) in order to determine the intrinsic tool precision.

This has to be differentiated from a proficiency test that is performed under ‘real operating’ conditions (no pegs or limits placed on the ground). Up to 2013, specifications were such that, for each measurement, the buffer tolerance value to be used was the one of the validated tool used for the considered measurement. It is reminded here that the value to be used is not the actual Reproducibility Limit (RL) calculated in validation process but the corresponding RL class value (i.e. "1.0m" for RL inside (0.75m, 1.0m]; "0.75m" for RL inside (0.50m, 0.75m] or "0.50m" for RL below 0.50m.).

Some Member States reported that dealing with different buffer tolerances was created problems since:

It was perceived as ‘unequal’/unfair’ treatment by farmers (for a same parcel the buffer tolerance would be higher if measurement done with imagery than if done with GNSS devices);
It could happen that a CwRS zone could be covered by imagery from two types of sensors. Then, two buffer values have to be used over that zones.

So to ease processes, it was asked to find a solution allowing for the use a single buffer for all measurements made in the frame of OTSC in a Member State.

In 2011 and 2012, the JRC has performed proficiency tests using different types of VHR ortho-imagery and GNSS devices. Out of these tests, it was concluded that a single value buffer tolerance could be defined for all area measurements performed using GNSS and/or orthoimagery. However, that single tolerance value shall not exceed 1.25 m. This was also under the condition that, all measurement tools used shall be validated (validation test) for at least one validation class of buffer tolerance below the single value (‘real’ conditions test). These rules were used as basis for the elaboration of Article 38 (4) of Commission Implementing Reg. (EU) No 809/2014.

Some recommendations for the Single value buffer tolerance

The maximum limit of buffer tolerance is 1.25m which corresponds to the maximum ‘inaccuracy’ limit accepted when dealing with features managed at 1/5000 scale. Member States should pay attention to invest in and use measurement tools as accurate as possible in order to ensure measurements well below the maximum tolerance.

Measurement tools used shall be validated for at least one validation class of buffer tolerance below the single value. This must be interpreted as: the single value buffer tolerance should not be higher than one validation class of the least accurate measurement tool used. For instance, if a Member State uses GNSS devices validated for 0.5m and VHR ortho-imagery validated for 0.75m, the recommended single value buffer tolerance is 1m.

For what concerns “the least accurate measurement tool”, some good sense or rationality is expected. If ‘most of’ measurements are done using devices validated for 0.5m and ‘only some’ are done using devices validated for 0.75m, it is expected to neglect the impact of the last ones and to use a 0.75m single valued buffer tolerance for all measurements. No numerical thresholds are given for ‘most of’ or ‘only some’. On that point, the Commission is expecting some common sense in MS administrations’ decision. In any case, considering the developments observed during the last years for GNSS devices, all devices acquired before 2017 and having a buffer tolerance > 0.75 m, should be considered as obsolete and discarded.

Other tools for physical field measurements

* Topographic survey instruments (single of dual frequency phase GNSS, electronic total station)

These instruments are normally used for re-measurement in the case of disagreement by the applicant and therefore they will be operated by skilled, professional survey staff. A statement of their precision for area measurement expressed as buffer width around the parcel perimeter (e.g. a certificate provided by the manufacturer or a validation test result) should be a pre-condition of their use.

Even if experience has shown that such instruments have a buffer width below 0.2m, a 0.5m buffer width is recommended.

* Wheel, tape

These systems are considered as backup tools for area measurements. These tools are primarily suitable for the measurement of lengths (strip width, offset measurements from parcel boundaries, track lengths), for which the geometry (shape) and slope is regular. The use of a wheel on rough ground is strongly discouraged. For lengths of up to 100m, a linear tolerance of 2% can be accepted. This is to avoid problems when the feature is not perfectly straight, and/or the terrain is sloped or irregular. Care should be taken with all such “analogue” tools to adjust the measured length to the projected (horizontal) length.

Above 100m, other tools (e.g. dGNSS) should be applied. In such case, a fixed linear tolerance value of 2 meters is used.

* Laser range-finder tools

These tools can be used for area measurement and could be also the preferred approach for distance measurements of absolutely straight features. They can be used for longer distances, provided that corrections for slope are possible and that the expected accuracy of the tools for such distance measurement is better than 2% linear length.

When to perform area measurement

It is reminded that, where the information on the parcel's boundaries in LPIS and/or in the GSAA reflects the field reality, no area measurement is needed. The declared area will be considered as determined.

When measurement is required, the two following options exist:

(1) The determination of ineligible areas and deductions.

Where the LPIS permits the confirmation of the "correctness" of the boundaries of the declared agricultural parcel, the area measurement may focus on the determination of ineligible areas and deductions. This method is only applicable where:

- the LPIS reference parcel is an agricultural parcel; or,
- the reference parcel is fully declared; or
- use is made of geospatial declaration of agricultural parcels, which allows an overlay of boundaries and eligible area as reported on the image;
- and areas not to be accounted for can be easily identified.
(2) Direct measurement

In all other circumstances than (1) an actual measurement of the parcel area is required.

Determination of area through deduction of ineligible features

The workflow below covers both ineligible features that are permanent or temporary as for area measurement their areas should be deducted from the maximum eligible area of the reference parcel / area of the geospatially declared parcel.

* When ineligible features of significant size (i.e. >100 m2) are identified in the parcel or,
* When ineligible features of minor size (i.e. <100 m2) are identified in the parcel, but exceeding 100 m2 when added up,

then, the determined area is obtained by deducting the area of these features.

The conditions on size of ineligible features are mainly linked to the need or no to actually map them afterwards in the LPIS.

For ineligible features > 100 m2 (like a pond) there is a need to delineate them and report them in the LPIS removing the equivalent area thus update the Maximum Eligible Area value of the corresponding reference parcels.

For ineligible areas < 100 m2, (for example bare rocks outcrops) there is a need to quantify and sum them and deduct them from the MEA-value. However they do not have to be mapped in the corresponding reference parcel.

However, some small ineligibility features <100 m2 can be identified whatever their size (artificial surfaces as roads and buildings) and should be mapped out.

Now, since these ineligible areas were 'discovered' during the OTS check procedure, there is a need to decide if the area should be deducted from the MEA of the reference parcel or it can be considered as non-significant and hence not deducted from the area declared by the farmer in the current year. The workflow to be followed is described in section 2.2.2. Determination of area through deduction of ineligible features/ areas of DG AGRI OTSC guidance (DSCG/2014/32 – FINAL REV 3 Final). In all other circumstances, the identified ineligible area will have to be deducted from the declared area of the current year.

Then, whatever the situation, the LPIS has to be updated, the farmer informed and the year campaign after will have to declare and be crosschecked with the updated value.

Combination of partial field measurements and on screen measurements

Combining partial field measurements with archive ortho-imagery may prove less time consuming than direct measurement of the whole parcel in the field. It could be an alternative to cases where measurement with GNSS equipment is hardly feasible due to obstacles, the nature of the area to be measured (e.g. common permanent pasture areas) or due to the particular nature of the measurement requested (e.g. permanent tree crop). The inspector should find a starting and ending point for the field measurement (encompassing the invisible border on the image) that are clearly identifiable on both the image and the field. Since this field measurement should be accurately repositioned on the ortho image, the measurement should be performed with precise tools (e.g. dGPS). Then the single tolerance value is applied to the total perimeter.

Determination of parcel area, use of technical tolerance

If a measurement is done, a tolerance can be applied in most cases to take into account the uncertainty of the tool used.

If such, then where the absolute (unsigned) difference between the measured and declared area is greater than the technical tolerance (expressed as an area in hectares to two decimal places), the actual area measured through physical measurement will be considered determined. In the alternative case i.e. when the declared area is within technical tolerance of the measured area (below reported as the confidence interval) the area declared will be considered as determined.

As from 2015, a unique buffer tolerance of maximum 1.25 m shall be used for area measurement related to agricultural parcels. This area tolerance is calculated by multiplying the parcel outer perimeter by the unique buffer tolerance value.

Applying technical tolerance to decide on acceptance or rejection of declared area in case of area measured


Determination of the scheme group area

The area at each scheme group level will be determined by summing up the individual areas of the agricultural parcels determined as described above. Over and under-declarations at parcel level can thus be compensated.

* for crop diversification, the area at the crop group level will be determined by summing up the area of each single crop;
* for EFA, the area at the scheme group level will be determined by summing up the area of each individual EFA declared fulfilling the conditions for EFA (until the "5% EFA" is achieved).
* for permanent grassland, the area at the crop group level will be determined by summing up the individual areas of permanent grassland which are environmentally sensitive and other areas of permanent grassland.

Minimum size

The minimum parcel size applicable in a Member State has to be checked. Parcels found below this minimum parcel size are not eligible for aid and should be flagged with an appropriate code.

Parcel area measurement in the frame of greening

Information provided so far remain valid for parcel area measurement to be performed in the frame of crop diversification and also for EFA crop like features (i.e. nitrogen fixing crops, catch crops). These rules do not apply for all other area measurements to be done on the frame of EFA (landscape features). For such areas, please refer to the technical specification provided in the Technical Guidance document on the On-The-Spot Check of Ecological Focus Areas requirements (DS-CDP-2015-09-FINAL)or on the following page OTSC_EFA EFA check

Afforested area measurements

Several of the rural development support measures are based on area, and a few of these concern afforested areas. These may be the case for first afforestation of non-agricultural land, Natura 2000 payments, and forest-environment payments. Since measuring in afforested areas is in general difficult (with GNSS due to the risk of signal loss, on ortho imagery because parcel boundaries may not be visible), MS are encouraged to look for individual solutions adapted to their landscape, LPIS reference system and available data (number of claims, existence of professional survey tools). Validation tests of GNSS equipment (with adapted settings) may also be carried out. In such situation, MS may define appropriate tolerances, which shall in no case be greater than twice the tolerances set for parcel area measurements for OTS checks in first pillar. This means that MS may use a buffer tolerance of maximum 2.5 m applied to the perimeter of the parcel, with an absolute maximum of 2.0 ha.

Area measurements for permanent crops

Apart from specific support for the vineyard sector (e.g. restructuring), permanent crop parcels are part of the BPS/SAPS scheme and thus standard eligibility and area measurement rules apply.

Limits and eligibility of areas in a permanent crop parcel will be determined according to evidence of management as permanent crop as an homogeneous unit of land.

For the details of specific support of the vineyard sector, please see the Guidelines for the implementation of certain provisions of the National Support Programmes in the Wine Sector. [1].

Diagnosis and codes for area measurement checks

At the end of the OTS check process (i.e. after the pre-CAPI check, the CAPI, other evidence or RFV), each claimed parcel should be assigned at least one code concerning the area and a retained area. The roles of the technical codes are the following:

- Trace the work of the operator (e.g. for quality control purposes);
- Allow to determine the retained area for each claimed parcel;
- Describe the possibly area error found;
-Allow a posteriori analysis and identification of particular problems (e.g. high occurrence of a given code in a region).

When the area measurement is done, the comparison is done with the declared area taking into account the defined single buffer tolerance. In cases where the agricultural parcel is composed of several cadastral parcels, computing the tolerance at the level of internal cadastral parcel would lead to the application of an excessive technical tolerance.

Therefore, the single buffer tolerance has to be applied on the perimeter of the agriculture parcel only or on the external perimeter of contiguous agricultural parcels.

Area measurements always have to be done to limit the artificial elongation of parcel perimeter. See following illustration.

CTS artificial Perim.PNG

A series of “standard” codes have been defined in relation to specific conditions. Codes have been defined together with diagnosis of Land use / cover aspects. For the details on codes, please refer to the dedicated chapter in Land use / Land cover checks.

Capping to the reference area

As a general rule the area(s) retained for the Basic Payment Scheme (BPS, SAPS) should not exceed the maximum eligible area of the corresponding LPIS reference parcel. A similar cap applies in the case of a reference parcel containing several agricultural parcels. In particular, when these parcels are declared by different farmers, a proportional reduction of the retained areas may be applied. In any case, the contractor has to refer to the instructions of the national Addendum. Finally, if the LPIS reference parcel contains several crops eligible for different area-related aid schemes, capping to the LPIS area applies individually for each scheme. Also, the spatial information associated to arable land, permanent grassland and permanent crops, and recodered in the LPIS, should be taken into account.

Land use Land cover checks

The purpose of on-the-spot checks linked to land use / land cover will consist in checking at least:

- the declared land use or land cover to the extent requested by the regulation (BPS, SAPS, Greening, VCS, Rural Development support …);
- the number and/or position of landscape features where necessary;
- the respect of the cross compliance requirements and particularly of the Good Agricultural and Environmental Conditions (GAECs).

Classical field check

Field inspection should be undertaken by operators having a very good knowledge and specifically trained in eligibility rules, cross compliance rules, and crop identification. Indeed, the check, for instance, of compliance of mixture of crop species in catch crop parcels may require very good competence in plant identification and taxonomy.

Field visits should be made at the best possible timing for identifying the crop(s), assessing its extent and/or assessing the quality management of the parcel.

Field visit documents such as maps for the overall location of the parcels and detailed location documents (e.g. parcel boundaries overlaid on a VHR image) should be in possession of the controller. Alternatively, navigation systems based on GNSS and systems allowing the display of images, vectors and data on a mobile computer in the field are highly recommended. It is recommended to take digital photographs of the parcels visited and especially for parcels with problems, and store them in a database. Each photo should come with its geo-location, a parcel identification number, date and time of the image shooting, identifier of the operator. These pictures may be presented to the applicant or an auditor in a follow-up meeting, thus reducing the number of follow up field inspections to a minimum. (see paragraph dedicated to geo-tagged photos) Finally, predefined codes should be used to report on the actual land use/land cover and any anomaly found.

Use of ortho-rectified imagery

Land use / land cover aspects may be checked by Computer Aided Photo Interpretation (CAPI) of current year imagery and can be supported by the use of automatic classification (supervised or unsupervised). The CAPI of agricultural parcels will normally be carried out using at least one very high resolution (VHR) image (satellite ortho-image or aerial ortho-photo with a pixel size <0.75m (in some cases, like for the check of EFA landscape features pixel size <=0.50m)) of the current year. In addition to the VHR image, multi-temporal high resolution (HR, or HHR) images may be provided upon detailed justification by the administration. It is also strongly recommended to use the Copernicus Sentinel 1 and 2 data. Depending on the agricultural land characteristics, staff availability, importance of the different schemes, some Member States may opt for a CwRS method based on the use of one VHR imagery to perform area measurements checks. Then, all checks concerning land use / land cover aspects will be done through Systematic Rapid Field Visits. In the former SPS/SAPS CAP rules, the need to identify individual crop types was not very strong. With the entry into force of the ‘greening’ and especially the crop diversification requirements, there is a need to identify crops at parcel level (as it was the case during the ‘couple payments’ CAP period i.e. 1992-2004).


The interpreter’s work can be summarized as follows:

- detect non-eligible features (water, building, forest) in the considered Member States;
- pay special attention to trees on arable land (100 trees/ha eligibility criteria);
- check the crops subjected to coupled payments;
- where the Administration has decided to use remote sensing for the control of the GAECs, all declared parcels of the holding should be inspected;
- where the Administration has decided to use remote sensing for the control of 2nd pillar (land cover related Agri Environmental Measures), all parcels under contract should be inspected.

We remind that interpreters should be specifically trained for checking all schemes related elements to be checked though imagery. They should be provided with common OTS checks guidelines. During the photo-interpretation stage the interpreter must be able to simultaneously display several images (e.g. a VHR ortho-imagery and a multi-temporal suite of HR ortho images) and also the vector and alphanumeric data for each application. They should have the possibility to display on-screen examples of parcels for which a preliminary ground survey has been done, and ground truth is collected. They may also have the possibility to display and make use of of series of "imagettes" and/or temporal profiles of Sentinel 1 and 2 data of the parcel under inspection (see

The classical false colour composite (near-infrared, red, green) is in general sufficient for checking the crops/uses that need to be discriminated. However, in case images with more than 3 bands are provided, it is advisable to select and use different band combinations depending on the features or crops under inspection. The band combination usually includes the near-infrared one, the mid (or short-wave) infrared and one of the visible bands. The use of multi-temporal indices (e.g. NDVI image) is another option providing useful ancillary information.

In case the crop check is supported by an automatic classification, it is recommended to never use the result of classification ‘blindly’ and always have a step of visual inspection of all parcels to confirm the diagnosis. When classifications are used, the classification process should be documented and detailed quality control records should be provided. Explanation should be given on how the classification results are used in the parcel categorisation (e.g. as an ancillary image layer helping the interpreter or as automatic parcel flagging).

BPS/SAPS land use / land cover Checks

In practice, land use check for BPS/SAPS will consist in checking compliance of the parcel with eligibility conditions. In essence, the CAPI work will mainly consist in focusing on the identification of non-eligible land (built up zones, rocks, transport network, ‘negative list’). Interpreters should be trained in detecting these elements. It may also be of help to use classification algorithms for the detection of these crops or land covers. Although parcels not claimed will have no impact on the diagnosis, checking these parcels allows to better check claimed parcels (in case parcels not claimed share a reference parcel with claimed parcels) and to train the interpreter on specific crops (e.g. crops that may not be eligible for BPS/SAPS).

Cross Compliance Check

Remote sensing data may be used in two ways for the control of cross compliance:

- Use of RS for a partial control of the GAEC.
- Use of RS as a support for the selection of the cross compliance sample (risk analysis).

Imagery use as a partial control of cross compliance: Some GAEC (or SMR) may be checked on satellite or airborne imagery. This is the case for instance for the maintenance of a soil cover during winter, the prohibition of burning cereals stubble, or the maintenance of some landscape features. According to the minimum requirement defined for a given act or standard, MS may decide to use RS images to check specific conditions (e.g. requirements that need to be checked during autumn or winter). In practice, during the photo-interpretation of the satellite imagery the CAPI operator will flag any case of possible non-compliance (e.g. doubtful land use) with an appropriate code. In addition, cases of non-compliance in respect of some GAEC that would be observed during a RFV should be reported to the Administration.

One should note that the availability of Sentinel data with very high temporal revisiting capacity can strongly facilitate the detection of some elements/activities. This is the case for instance for the depiction of brief events like the burning of stubbles.

Imagery use as a support for selecting the cross compliance sample: On the CwRS OTSC sample or on the whole area covered by Sentinel HR images, an automatic classification (refined by CAPI) could provide a list of parcels potentially in breach with some GAEC. The corresponding dossiers may hence be part of the risk based sample for the controls of cross compliance of a given control body (the “1% sample” per competent authority). Administrations should clearly describe the option(s) retained (no control of cross compliance with RS, use of RS for partial control or for risk analysis) for each of the control zones. If relevant, the GAECs to be checked and the criteria to be assessed should also be described as well as the specific imagery / processing requested (e.g. RADAR imagery in winter for the detection of bare soil).

Voluntary Couple Support Check

Methodologies to identify crops under VCS scheme are the same as the ones needed in the frame of crop identification to check compliance with the ‘diversification’ requirements. So for this section please refer to the ‘crop diversification OTSC technical guidance’ (DS-CDP-2015-08–FINAL).

Crop Diversification Check

For this section please refer to the dedicated ‘crop diversification OTSC technical guidance’ (DS-CDP-2015-08–FINAL).

Ecological Focus Areas Check

For this section please refer to the dedicated ‘Technical guidance for the On-The-Spot check of Ecological Focus Areas (EFA) requirements’ [(DS-CDP-2015-09–FINAL).

Use of the monitoring system to complement CAPI work

As from May 2018, art. 40a of the Reg. 2018/746 amending the Reg. 809/2014 2014/809 introduces the possibility to substitute OTSC by a system of checks by monitoring. This system is mainly based on the use of free Sentinel 1 and 2 satellites imagery.

Time-series processing as the ones used in the frame of monitoring can be used to provide additional information for the diagnosis of land use/land cover at parcel level.

Principles to photo-interpret Sentinel data temporal extracts are the same as the one used for ‘traditional’ CAPI using 2 to 5 dates of combined VHR/HHR data. Spectral resolution of Sentinel-2 still allows reliable visual discrimination of the major agricultural land cover types on several well-positioned images, if the appropriate spectral bands are selected. The spatial resolution is, however, inferior compared to HHR, which means that the physiognomic and structural aspect of the vegetation would be less apparent (prominent mostly in the case of permanent grasslands and permanent crops). Nevertheless, it is somehow compensated by the increased Sentinel 2 temporal resolution, which allows to obtain much more observation dates and to build temporal profiles that can be very much associated with crop/plant phenology. Possible identification/discrimination of crops/land cover/land use will depend on the phenological development and time when different developing phases occur. Identification will then depend on the good knowledge of regional/local phenological calendars. This knowledge is the same as the one used from operational CwRS CAPI methodology. Tools to extract and display the relevant Sentinel data in the dedicated visual environment for CAPI inspection (cf. figures below) could be made available through cloud computing solutions This eliminates the needs to download and process locally Sentinel data. Two main visual modalities are envisaged: (1) Temporal profile – It is a graph showing the evolution in time of a given signal parameter (individual image band or derived indices), extracted from each Sentinel (or equivalent) temporal observation. It is usually calculated from all image pixels found within the declared parcel.

Catalunia alfa.jpg
Example of Sentinel2 NDVI temporal profile extracted for a parcel declared as Alfalfa. The blue line represents the NDVI mean value calculated from the pixels within the parcel, while the vertical bars show the NDVI standard deviation from the same pixels.

Similar temporal profiles (backscatter, coherence ...) could be extracted and generated from the SAR data, acquired by the corresponding Sentinel-1 (see example below). SAR-derived profiles have the advantages of being relatively not influenced by clouds and haze; however, their visual interpretation is not so intuitive, and requires some specific knowledge on SAR technology and the nature of the signal.


(2) “Imagettes” – these are consecutive time series of image chips extracted from each Sentinel 2 observation. The image chip usually encompasses the declared parcel together with a buffer zone around it. It could represent the raw image data (band combination used for visualization is normally 8, 11, 4) or derived indices (for example NDVI calculated at pixel level). The series of image chips “Imagette” are the closest to what the CAPI operators are used to work with in the current CwRS setup. They can be organized in an array with rows being the months in the year and the columns being the half-weeks within the month. The example below lists all corresponding Sentinel 2 (cloud free) Imagettes available for the parcel with Alfalfa shown above.

Cata calendar.jpg

Tools to extract information, for a specific parcel, have been developed by the JRC. (Please contact JRC for information). Another supporting tool of interest is one allowing to display temporal profiles of parcels declared with similar LU/LC in the considered parcel ‘vicinity’. See example hereafter, this hugely facilitates the comparison between parcels with similar use/cover in the period of interest.

Maize medio.jpg
Mean profile (dark green) and standard deviation (light green) of silage maize parcels from declared GSAA in the country. In pink color, profile of parcel under inspection

For more information concerning the monitoring system approach, please refer to the documents on the checks by monitoring to substitute OTSC (DS-CDP-2017-03), (DS-CDP-2018-17) and (DS-CDP-2018-18) and do not hesitate to contact the JRC.

Codes for diagnosis

In classical Control with Remote Sensing (CwRS), i.e. control performed mainly in the office, diagnostic rules are applied at parcel, group and dossier levels. The objective of these rules is to separate the dossiers that will need a field visit from those which are considered as correct and therefore do not need any follow-up action (for the points that could be checked by remote sensing). Several codes may be used simultaneously. When several codes are assigned to a parcel, the retained area and land use should correspond to the least favourable condition. Some codes are likely to change after a rapid field visit. In the latter case, it is recommended to keep track of the two successive situations: i.e. to keep the code(s) before and code(s) after the rapid field visit. In the frame of the control of cross-compliance, specific codes should be applied to flag parcels for which a breach to a specific GAEC or cross compliance issue is observed or suspected during the CAPI process. In the frame of control of greening conditions, specific codes should also be applied. A series of ‘standard’ codes have been defined and classified in three categories (see table below):

- The Tx codes are assigned during CAPI to parcels not checked for some technical reason beyond the interpreter’s control (e.g. parcel outside the image). As assigning a T code implies giving the benefit of doubt to the applicant, these codes should not be assigned to parcels deemed doubtful during CAPI.
- The Ax codes correspond to anomalies, in particular those related to eligibility, and lead to the rejection of part or a totality of the parcel.
- The Cx codes are assigned to the interpreted parcels (i.e. checked parcels) but for which the declared area (or crop) is not accepted by the interpreter. Different rules apply for computing the retained area.

If relevant, several codes could be assigned to the same parcel. If both the declared area and the declared ‘land use/land cover’ under inspection are accepted, the controlled parcel will be coded as “OK”. Additional codes may be defined by the National Administration to record specific cases not described by existing codes (e.g. LPIS boundary to be updated, or codes for other schemes). In order to avoid confusion it is preferable:

. not to reuse already existing codes (by changing their definition);
. to create new codes by subdividing existing codes: for example A31 (unknown cadastral reference), A32 (valid cadastral reference, but no vector).

Moreover, the new code(s) should be connected to an existing category (T, A, C) as much as possible. Calculation of retained area: The last column of table below indicates which area should be retained at parcel level and therefore transferred to the crop scheme (group) level. Table of standard codes related to the CAPI conditions encountered at the parcel level, and proposed rules for the calculation of retained area

CTS Diag codes.PNG

Rapid Field Visits

Rapid Field Visits (RFV) are directed to problem or doubtful parcels identified during the CAPI possibly complemented by any other kind of evidence (see following paragraph). Thus, they will be intended to check the land use / land cover and possibly some cross compliance issues (GAECs) in the field without contacting the farmer. Results of the RFV should be used for completion of the diagnosis at parcel level. Detail description of the possible RFV workflow is given in the technical guidance of the LPIS quality Assessment section in WikiCAP. It is advised to take digital photographs of the parcels visited and stored in a database with their location, to be presented to the applicant in any possible follow-up meeting, thus reducing the number of follow up field inspections to a minimum. Field visit documents such as maps for the overall location of the parcels and detailed location documents (e.g. parcel boundaries overlaid on a VHR image) will have to be provided to the staff in charge of RFV. Alternatively, navigation systems based on GNSS and systems allowing the display of images, vectors and data on a mobile computer in the field may be used. Predefined codes should be used to report on the actual land use and any anomaly found. Finally, results of RFV may be used to assess the quality of the CAPI diagnosis work. Thus, the diagnoses established before and after RFV should be recorded.

Alternative solutions to evidence Land Use / Land Cover

Out of the RFVs, Member State Administrations may use alternative solutions or data capture tools in order to conclude diagnoses on the parcels under check.


Unmanned aerial vehicles (UAVs) or Remotely Piloted Aircraft Systems (RPAS) better known as drones offer low-cost aerial VHR camera platforms. These devices allow very fast VHR image data capturing and tools for ortho-rectification processing are available on the market. Products are thus easy to integrate in the IACS-GIS. While having a limited capacity of area coverage (some km2), they offer the possibility to be operational on demand within few hours. They could be used, in absence of satellite imagery, to acquire images to check the presence of catch crops in a small region or to check the presence of winter cover. It can be also a useful solution to check parcels that would be difficult to access on the ground (e.g. in semi-mountainous areas, swampy areas …).

Geo-tagged photos

Geotagging is the process of adding and embedding geographical information, and possibly additional temporal and/or textual information into the metadata file of a photograph. The location and time of acquisition will be obtained through the GNSS antenna of the photo camera or smartphone. Member State Administrations should strongly consider the utility of this low-cost, readily available, and easy to use technology. They could integrate, in their IACS, geo-tagged photos provided by farmers as evidence of compliance to specific conditions or rules. For instance, a farmer could send a geo-tagged photo of his Durum wheat field(s) being part of a Voluntary Couple Support. Also, a Geo-tagged photo could be sent of a grassland just mowed to show compliance with a mowing date imposed by the legislation. The provision of such geo-tagged information will avoid the field visit that otherwise would be necessary. Today, different devices offer the possibility to capture geotagged photos such as digital camera, smartphones, tablet PCs or even GNSS devices.

You can find further information that the ones provided below in the JRC technical report on Geo-tagged imagery

a) The minimum information

The minimum information to be embedded or stored, for each image taken, should consist of:

- Its date and time of capture;
- Its geographical location;
- Its orientation (image heading);
- The identification of the operator;
- Information on the device.
- It is also recommended to register the elevation and the Dilution Of Precision (DOP). This last parameter gives a qualitative indication on the positional precision.
- The date and time

The date and time of photo capture should be registered directly through a GNSS antenna (internal, external) of the device. Manual geotagging, by setting date and time directly through the device menu, should be prohibited as it introduces possibilities of error or manipulations. Even if embedded in the metadata file, it is advised to also automatically stamp the date and time on the photo.

CTS Tag encrypt.PNG

Example of automatic encryption of date and time in a photography

- The geographical location

As for the date and time, the location (longitude, latitude coordinates) of photo capture should be registered directly through a GNSS antenna of the device. It is possible to enter directly the coordinates in the device or by selecting a location from a map using software tools, but this manual geotagging should also be prohibited.

It is reminded that the antenna of the device gives the position. For device with external antenna, instruction must be given to place it close to the camera lens. It is also important to stay still some seconds on the viewpoint before taking the picture.

Currently, internal antennas of smartphones, tablet PCs, digital cameras provide a positional accuracy of some 10 to 20 meters. It is important to reduce this uncertainty to a meter, sub-meter one. This may be achieved indirectly by taking the picture close to the border of the parcel and identifiable landmark (e.g. a corner of the parcel see example hereafter).

CTS Tag landmark.PNG

Photo with identifiable landmark allowing to ensure its correct location While not yet available, there is a fast developing technology, which very soon should provide solutions to improve the positioning accuracy. One can site among others: EGNOS compatible smartphones, low-cost sub-meter accuracy external antenna, or even smartphones with dual frequency GNSS receivers.

- The orientation

In addition to the location, it is important to ensure that the operator was pointing at the right targeted parcel. Thus, information on the direction (heading) the camera was pointing must be collected. This could be obtained directly from a compass system embedded in the device but most of current ones are vitiated by a +/- 10 degrees deviation. As alternative solution, and if existing, the operator should point the camera toward a feature/ a landscape element that could be easily depicted afterwards on ortho-photomaps (see example below);

CTS Tag orienta.PNG

Example of photo containing elements allowing determining the direction the camera was pointing when shooting the photo. Some applets using augmented reality technology are also now available. It allows superimposing the limits of the reference or agricultural parcel of concern, live on the screen view. The photo orientation is deducible from this overlay.

- Identification of the operator

A procedure should exist to identify the operator (in most of cases a farmer) providing the photo. This can be obtained using a system of authentication through personal login and password prior to upload a photo in a dedicated database.

- Information on the device

As part as the information needed for any possible check of the photo content integrity, as a minimum the type of camera model and the focal length should be registered.

b) The image format and quality

Today the main image file formats are JPEG or JPG files (Joint Photographic Experts Group), TIFF or TIF (Tagged Image File Format) and RAW. JPEG is the far more common file format for photos and often the only format available in digital cameras. However, with JPG format, the image is compressed when recorded. This may induce loss of image details if the compression level is too high. So, devices should be set to ‘Low compression JPG’ or ‘fine’ format to limit distortions (even if photo size will be bigger). One has to note that most recent cameras allow creating and recording a RAW image and a JPEG image at the same time (RAW+JPG). This setting maybe suitable to limit possibilities of image manipulation. However, since no compression is done on RAW images, their size will often be 2 to 3 times bigger than the JPG equivalent ones. In most areas in Europe, internet and/or GSM bandwidths will be too coarse to allow transferring these RAW format images. The camera resolution should be at least of 5 million pixels. This size consents to display and possibly magnify the view without becoming too blurry or "grainy" thus allowing to identify features in the picture. Instruction should be given to ensure a good exposure of photos (e.g. not facing the sun, no dark conditions …) to obtain usable and exploitable images. Last but not least, attention should be paid to some privacy aspects. As example, no people or car plate should be visible on image captured.

c) The minimum number and type of photo

The number and type of photos (e.g. general view, macro …) will depend on the land use/land cover or any other element that need to be provided as evidence. Nevertheless, it is recommended to provide at least 2 photos of the element taken from different viewpoints or view angle (as exemplified hereafter). Photos taken from 2 different viewpoints allow to have a rather comprehensive view of the element. Photos taken from same viewpoint but with 2 different view angles allow to limit the possibility of image manipulation.

CTS Tag viewpoint.PNG

Parcel in image 1 seen from 2 viewpoints (2 and 3) and 2 view angles (3 and4)

Sometimes, a “macro” photo will be needed as evidence (e.g. presence of Durum wheat for VCS, mixture of crop as EFA cover crop…). Another photo should be captured from the same viewpoint, with the camera pointing higher at the horizon showing the corresponding field. One should note also that many devices present now the possibility to capture 360 degrees or panoramic photos. In some circumstances, this type of format maybe represent the optimal evidencing option.

d) Information integrity and security

Administrations should develop a standard operating procedure to ensure the information integrity and security of geo-tagged photos transfer; in other words, ensure that the whole information content has, in no manner, been falsified. Some administrations have already developed dedicated smartphone/tablet applets to be used by farmers (or by inspectors) using combinations of solutions to avert tampering with data. As example, a photo is blocked for upload if not sent within few seconds after capture (in case a GSM network is available for transfer at the location of picture capture). Alternatively, a code is encrypted in the photo at capture and its integrity checked at administration’s database entry. Also, over the last decades, standard detecting image manipulation techniques have been developed that are based on pixel, format, physical or geometrical processing (so-called forensic analysis). Geo-tagged images should be stored in their original file formats. It means that no additional compression process other than the one done at data capture (JEPG) should be performed since critical image information may be lost and artefacts introduced. Files should also be stored as ‘read-only’ to avoid modifications or deletions. Any viewing and/or manipulation of photos should be done on a copy of the original one. For more information on data security see Chapter 7 of the JRC technical report on Geo-tagged imagery

Other ancillary digital information

Some current legal requirements may prove to be very difficult to check using satellite imagery or even in the field like the check of presence of Durum wheat as part of Voluntary Coupled Support or the check of a cover crop mixture as part of the EFA greening scheme. Member State administration may consider the use of ancillary information to be sent by farmers like a scan or a digital photo of the tags bags or invoice of purchased seeds. Having these document geo-tagged will not bring useful information. It is however more important to ensure that the name of th farmer, the date of the invoice and the quantity of seeds appear on the invoice.

Categorisation at scheme group level

For each scheme group, the total declared area of the crop group (Dg) will be compared to the total retained area of the crop group (Mg). In practice, the areas declared and retained for all parcels claimed in a given scheme group are summed, therefore allowing compensation between over-claimed and under-claimed parcels of the same scheme group (if this compensation is allowed in the Member State concerned). Sorting of scheme groups into ‘Accepted’ and ‘Rejected’ For a given scheme group, the following three cases may be encountered:

- A1: The declared area is equal to the retained area (Dg - Mg = 0).
- A2: The declared area is less than the retained area (Dg - Mg < 0). In this case, the Administration will accept and pay only the claimed group area.
- R: The declared area is greater than the retained area (Dg - Mg > 0).

The first two categories are considered as accepted. All scheme groups with a declared area greater than the retained area (third category) shall be rejected. Sorting of rejected scheme groups into minor and major rejects As any rejected scheme group should be subjected to a follow-up action, since it incurs reductions or sanctions, a second test may be performed in order to sort minor and major rejects. This test, which consists in comparing the discrepancy (Dg - Mg) with some threshold to be fixed by the Member State, is useful when the follow-up action varies according to the discrepancy. As per default threshold value, (Dg - Mg) > 3% Mg or 2 ha can be suggested. If higher than the threshold, the scheme group is classified as RMa (major rejection) if not it is classified as RMi (minor rejection). Obviously, if the follow-up action is the same for all rejects (e.g. letter sent to the farmer and field inspection in case of no reply within a number of days), sorting the rejected scheme groups appears as unnecessary. The follow up actions for minor and major rejects are of the responsibility of the Administration. Attention has to be paid to establish a diagnosis for the BPS crop group, indicative diagnosis may have to be recomputed accounting for the payment entitlements before starting any follow-up action.

Categorisation at dossier level

There are three steps in the categorisation of the dossiers: A conformity test; a completeness test; and a final diagnosis per dossier combining the two previous ones.

Conformity test

A dossier is accepted if all crop groups are accepted (i.e. Dg-Mg <= 0 for any scheme group). The table below summarizes this test for Member States making a distinction between minor rejects (all crop groups are minor rejects) and major rejects (i.e. at least one crop group is a major reject) at dossier level. The proposed coding (DMi and DMa) remains valid whatever the test applied for sorting the rejected dossiers (e.g. fixed threshold in ha or monetary unit). If no sorting is applied (i.e. all rejected dossiers are processed in the same way), the categories DMi and DMa could be amalgamated into one category coded DR1. For dossiers concerned by BPS scheme, the categorization (as Accept or Reject and for the Rejects, as minor or major Rejects) will be considered as provisory as long as the payment entitlements will not have been taken into account. This provisory categorization may be used as an indicator of the quality of the application.

CTS categorisation.PNG
Completeness test

The purpose of the completeness test is to avoid accepting a dossier which has been checked on a too restricted extent due to technical problems, i.e. T codes. In such a case, the dossier is considered as not having been controlled by remote sensing. If the dossier was part of the control sample, it has to be completed it in the field, i.e. field inspected. A dossier will be categorized as "complete" if the percentage of parcels with T codes with respect to the claimed parcels is lower than 50% (Cf. Table below).

CTS Completeness.PNG

In order to improve the efficiency of the control, applications sharing a reference parcel with any application from the control sample may be included. This recommendation is valid for any type of OTS check (physical inspection or CwRS), and particularly for checking joint cultivations, but is probably easier to apply in CwRS than in physical inspection. Such ‘ancillary’ applications are likely to be incomplete and should hence not be completed in the field, in contrast with the applications from the control sample. However, although very partially checked, these applications could be rejected on the basis of irregularities found on the parcels checked.

Final diagnosis at dossier level

The final diagnosis summarises the diagnoses of the conformity and completeness tests at dossier level. This table below proposes a general diagnostic code per dossier and describes a possible follow-up action to be undertaken for rejected crop groups or incomplete dossiers. It is reminded that incomplete dossiers that were part of the initial control sample have to be completed in the field. In some Member States, the contractor may be in charge of the RFV necessary to complete the dossier (Cf. National Addendum). The general diagnostic code proposed takes account of the distinction between dossiers rejected for minor and major discrepancies. If such a sorting is not used, the diagnostic codes can be simplified (e.g. DR7 and DR8 for rejected complete and rejected incomplete respectively). Whatever the diagnosis at dossier level, Member States may decide to manage parcels outside tolerances by appropriate administrative procedures, in particular if the anomaly originates from the LPIS. A dossier categorized as incomplete will be counted and paid to the contractor if it has been processed and photo-interpreted normally. It neither will be counted nor paid if it appeared incomplete before the digitization and the photo-interpretation.

CTS Diag dossiers.PNG

Production of OTSC report

Although there is no OTSC report template currently provided by the Commission, Article 41 of Regulation (EU) No 809/2014 lays down the mandatory elements of the OTSC report. Accordingly, it is recommended to develop and use a common digital control report. This digital form should contain predefined lists of required information. In addition to the elements foreseen in the above-cited Article, it is preferable that the report contains at least:

- Names of person(s) conducting the inspection;
- Date of inspection;
- Measurement tool used along with its specific settings (e.g. GNSS measurement in vertex or continuous mode, scale of CAPI digitalization);
- Detailed summary of inspection findings (parcels okay, parcels flagged or rejected, documentation and codes for the rejection, screen shot and/or field photograph of the problem found, geo location of the parcels, possible follow-up action)
- Document all parcels for which an LPIS concern has been identified and for which a follow should up be done by the competent LPIS custodian;
- Document all parcels for which an EFA concern has been identified and for which a follow should be done by the competent EFA layer custodian;
- …

For all information that is considered as mandatory (e.g. inspector name) it is advised to prevent the form from closing as long as these fields remain unfilled.

Sign and certify each inspection report.

Each inspection report must be signed and certified by the permittee to be considered complete. Where inspections are carried out by a contractor or subcontractor, it is recommended to also have the form signed and certified by the inspector, in addition to the signature and certification required of the permitted operator. The template report should include a signature block for both the administration and the farmer.

Copies of all inspection reports with all records must be retained for at least 10 years.

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Analysis of the campaign – Act for the next campaign

In this section, some statistical procedures and other good practices are suggested in order to take the best advantage of the control results and thus to prepare the next campaign year in the optimal conditions.

Quality Controls

It is important to implement a quality management in all OTSC procedures. This quality control process be can performed internally and/or targeted to the contractor. Any contractor is required to carry out an internal quality assurance which will result in quality control records. These records should be kept for inspection by the administration.

It is advised to perform an independent external quality control. This was formerly carried out by the Commission on one control zone per contractor. As from 2009, the JRC stopped this regular check of all contractors. However, after the entry into force of the new CAP rules and on specific request by a MS’s Administration, the JRC can provide support and carry on a QC process. To do this, the MS Administration has to prepare and provide a set of data (i.e. LPIS and interpreted vectors, orthorectified imagery, orthorectification Quality Control Records (QCRs), declaration data, measured and retained areas at parcel level) corresponding to one CwRS zone.

Ideally, the quality controls should be spread on the whole CwRS zones. This would also enable to check the consistency and homogeneity of the controls over the country/region. As a general rule, it is also recommended to verify in the field a minimum number of the accepted dossiers from a selected control zone. As dubious dossiers are consistently checked in field, it is considered that there is no need to check them again during the QC. For each control zone, the number of dossiers to be verified and the quality acceptance threshold (i.e. maximum number of dossiers with initial diagnosis not confirmed) are determined by the standard ISO 2859-1:1999 (AQL set to 1,5% with a simple sampling plan and normal inspection).

CTS QC numbers.PNG

In practice, and using the last line of the above table as example, for a Paying Agency that had between 10000 and 35000 dossiers as part of the OTSC, 315 dossiers should be randomly selected. These dossiers will be (re)checked to see how many dossiers will have their initial diagnosis confirmed or on the contrary contradicted. At the end of this QC, if not more than 10 dossiers have their initial diagnosis disapproved, the process of OTSC is to be considered as efficient and reliable (statistically significant). If not proven efficient, at the end of this QC procedure, any inconsistency should be documented and the causes of such discrepancy should be identified (e.g. lack of training, tiredness of the inspector, workload …) in order to take action to improve the OTSC processes and methods. The quality control should be carried out to assess also the suitability of CwRS for checking the GAECs, CD and EFAs requirements (and possibly SMRs related to environment) that the MS have decided to check with RS. In particular, during the inspection of the farms belonging to the GAEC sample, it is recommended to perform rapid field visits on a sample of OK parcels in order to ensure that no anomaly was overlooked by CwRS. In addition, the Member States have the responsibility to carry out an external quality control of the contractor's work.

Study of residual errors

The error rates are computed as the ratio of area not found on area declared. As those error rates are computed on a sample and not on the whole population, they must be considered as an estimator of the true error rate of the population. Thus, MS are recommended to analyse those results, taking the expected variability of this estimator into account. It is considered not sufficient to verify numerically that the estimated error rate is below some threshold (2% is typically the accepted limit). A proper statistical test may be set out to address the question “Is this error rate smaller than the 2% limit?”. Similarly, when comparing two error rates, their respective uncertainties may be taken into account in a test “Is the error rate A smaller than the error rate B?”. In this regard, the standard deviation(s) of the error rate(s) can also be estimated based on the sample(s). The formula for this estimation generally depends on the sample design(s). Specific formulas are detailed in Annex 3 as a recommended means of analysis. The exhaustive control of a zone (e.g. by CwRS) is a particular case because it is actually a control of the whole population over that zone. Consequently, the error rate computed on this particular zone is the exact error rate over that zone (i.e. there is no uncertainty and the corresponding standard deviation is equal to zero). Obviously, in this context, since this error rate is an exact value, it can directly be compared to any fixed threshold. However, a control zone remains a subset of the population so the error rate that is found over that zone is merely an estimator of the error rate of the population (i.e. general case as above). For instance, if the value found after an exhaustive control of a zone is equal to 1.75%, it is sure that the error rate of the zone is smaller than 2% (i.e. no test needed). But the value 1.75% is an estimator of the true error rate over the whole population and its standard deviation needs to be computed in order to assess whether it is statistically smaller than the 2% limit. (for more information see Residual_Error)

Analysis of the campaign

Information gathered though the campaign and especially based on the number of errors revealed or not revealed, taking into account the quality control phase should help administrations to reflect upon the setting of the OTSC methodology(ies) through:

- Considering the appropriateness of the various control methods applied in respect of the particularities to be controlled;
- Considering the links of the different elements within IACS (GSAA, administrative checks, OTS Checks, sampling, number and type of errors, pre-established information etc…);
- The appraisal of efficiency of the control methods: imagery and/or field;
- Detailed study of photo-interpretation and automatic classification processes; software and personnel, photo-interpretation keys;
- Analysis of the geometric and radiometric corrections of imagery;
- Analysis of the imagery use (usefulness of images ordered, relevance of acquisition windows, % of RFV on total parcels photo-interpreted …);
- Analysis of measurements made with other tools (mainly GNSS devices);
- Analysis of the working timetable and “bottlenecks”;
If relevant, analysis of share of work between administration and contractor partners; Estimate of the total number of dossiers processed each day;
- usefulness of ground data collection;
- …

‘Lessons learnt’ should also be combined with the outcomes of the LPIS Quality Assessment.

It is advised to formalise these findings producing an assessment report. Then, from the analyses above, it is also advised to produce a remedial action plan or textual description of remedial actions to be implemented for the following OTSC campaign.

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