ETS Inspection variants

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Reference parcel aggregation

The reference parcel aggregation method was introduced for agricultural landscapes where the visible cropping pattern often coincides clusters of complete reference parcels. The principle of crop aggregation is analogous to OTSC AP measurement, where a full crop group is measured if it spans several reference parcels. RP aggregation method is foreseen for cadastar and agricultural parcel designs.

Using the reference parcel aggregations option remains in principle optional, but it becomes mandatory where low “feasibility for measurement” results creates a methodological or perceived problem:

  1. a methodological problem arises when less than 200 reference parcel are measured as this is often the minimum sample size for LQ 12.5 indexed tests.
  2. a perceived problem can occur when more than 200 but less than half the RP measured. Indeed what is the true reference value of a LPIS when more than half of its reference parcels can not be measured?

So, application of the reference parcel aggregation is subject to an a priori decision made on LPIS quality assessment results from the previous year.

The estimated number of reference parcels that will not be feasible for measurement in the current year of assessment, can be equal to the sum of reference parcels found to be "not feasible for measurement" in the previous assessment year.

If that sum represents more than 50% of the inspected sample, then reference parcel aggregation becomes mandatory.

Any application of the reference parcel aggregation variant is systematic: if applied, aggregation and crop measurement needs to be performed for all sampled reference parcels where the conditions apply.


  1. By their very nature, all cadastral parcel and agricultural parcel designs could be more subject to the conditions that require reference parcel aggregation.

Field activities


The introduction of a limited number of dedicated LPIS QA image zones has two direct consequences:

  1. in areas with lower reference parcel density, there are fewer parcels in the sample pre-selection. It is no longer always feasible to skip an item, considering that the sample pre-selection list can be shorter than in ETS v5.3.
  2. there should be fewer logistical challenges to organize field activities.

Furthermore, field activities will yield a better overall inspection result as well as a better analysis of those results.

Finally, the EC services expect a raise in field activities as some inspections (classification correctness) might not be correctly assessed from the imagery alone.

Different types of field activities

ETS v6.1 still recognizes four processes where field activities are relevant:

  • field inspection - parcel inspection is fully based on GNSS field survey.
  • combined inspection - parcel inspection is based on merging CAPI delineation and field survey. This usually involves a border inspection in the field
  • perimeter inspection - inspection of a LUI to vindicate a critical defect (formerly called boundary inspection)
  • field observation - other activities complementing the normal CAPI inspection


All field activities are subject to a discretionary decision of the Member State whether it is to replace or support the CAPI inspection. However, that decision must be systematically, and not discretionary applied to all items in the sample. Any discretionary decision would lead to the inclusion of "nice" parcels in the sample and thus biasing the results of the ETS.

Conditional triggers

There are several alternative paths for item inspection. The path each item should follow is conditioned by the earlier findings on that item during ETS inspection. It is important to recall that any item can only follow a single path and cannot jump to activities that are not on that path. The path that an item follows will always determine the content of its inspection records of the ETS reporting package and will be subject to automatic screening during and after the upload of that package.

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