Reference parcel validity

From Wikicap - European Commission

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Once the update geometries and geometric areas have correctly been established, the question of their validity arises.

By definition, the reference parcel is valid on the date when the main source data (orthoimage or survey) was acquired.

One should assume that the reference parcel version should -as much as possible- still be valid on the time the update is implemented in the LPIS. This assumption should be assured by minimizing the delay between the capture of the source data and the processing of the anomaly. For this, the Commission services suggest following:

  • With the current state of technology, it should not take more than 3 months to create a unit of orthoimagery product (cartographic map sheet, photographic tile) after all relevant raw image captures for that unit of product have been acquired. If the processing is not done in house,, product delivery schedules should strive to:
  • either accommodate this three month delivery delay for regular deliveries or
  • ensure that products from raw imagery taken from February of the previous year to January of the current year are delivered by May of the current year.

The aim is to make the new images ready and available to be used by in the geo-spacial aid application process

  • To support the reporting of anomalies in good faith, the delivered orthoimagery should within a month upon receipt be made available to all farmers, inspectors and other personnel, even for zones not yet processed in the LPIS refresh cycle or project.

The start of validity of the updated reference parcel version (i.e. the date when the change affected the reference parcel in field and also the end of validity for the previous version), cannot be determined by the main data source alone. One can search for clues in ancillary data or third party data but such data might not be available or practical.

By contrast, systematic review cycles based on periodic image acquisition strongly reduce any adverse effects of this uncertainty as it enables observations on the one before last image. So, the Commission Services suggest that for the systematic review cycle or a refresh project, the system's imagery should support retroactive recovery up to three years. In other words for any year N, image acquisition dates should precede January 1 of year N-3.

If the reference parcel feature type is derived from third party data (e.g. cadastral parcel), timely data exchanges with all necessary metadata should organised with that third party.

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