Manifest change detection

From Wikicap - European Commission

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The concept of manifest changes serves a simple methodology to discriminate between meaningful changes and variations in appearance of the land.

The appearance of agricultural land changes all the time and so does the land cover that was delineated for LPIS purposes. Of these, many observed changes actually represent dynamic phenomena that are inherent to the agricultural land cover but that do not alter the character of that land:

  • Arable land has an annual cycle of crop and bare soil,
  • Hedges grow large for some years and are then trimmed back.
  • Agricultural land may be occasionally flooded

Such dynamics represent normal behaviour of the agricultural land covers. Neither do they affect the LPIS, nor do they require an update. Manifest changes are those other true changes of the agricultural land that are readily perceived and recognized by the sense of sight.

As their adjective “manifest” suggests, these changes should be easily and intuitively detected. The protocol below offers a more systematic way to ensure proper detection of true changes applicable to all conditions.

The detection of a manifest change automatically confirms the anomaly that documents it.


Figure 6 Analyse manifest changes

In the checks below, changes in agricultural land cover relate to either:

  • Changes from agricultural land into non-agricultural land or vice versa
  • Changes from one agricultural land cover type into another regarding these basic groups: arable land, permanent grassland, permanent crop, each type of grassland with scattered ineligible features,

The methodological steps are:

  1. Check for land cover (LC) changes along the borders: Observe, whether there are changes of agricultural land cover at the RP border in a strip wider than 2,5 m. If there are, document the cause as irreversible conversion of agricultural land cover.
  2. Check for LC changes inside the perimeter by observing any LC change that is bigger than 100 m2. If such eligible LC type has been changed into a non-eligible one then also document an irreversible conversion of agricultural land cover
  3. Check for permanent constructions above ground: buildings, roads or other processing, infrastructure facilities or any storage structures, stable at least 3 years, If found, document as appearance of permanent construction
  4. Check if new agricultural land has been added from outside the system. If there is, report a change in the perimeter due to addition of agricultural land.
  5. Check if agricultural land has been exchanged between reference parcels: If there is, record this change in the perimeter due to exchange of agricultural land,

The above procedure leads to the reported detection and classification of the nature of a manifest change, provided one is present. There is absolutely no need to document individual steps or outcomes where no manifest changes were detected. Below are some examples of manifest changes:



Figure 7: Conversion of agricultural land inside the parcel perimeter. In this case from agriculture to natural habitat. Note the disappearance of the road and appearance of creeks.



Figure 8: Conversion of agricultural land crossing the parcel perimeter



Figure 9: Irreversible conversion of agricultural land. Appearance of roads. In this case the new construction pushes the existing road into the reference parcel.



Figure 10: Example of splitting caused by the same construction.

Note that the reference parcel on the left has reached the end its life-cycle, it no longer represents a single unit of land. From the update onwards, two new reference parcels start their life cycle.



'''''Figure 11: Example of merging. Land consolidation has caused the merger and it can make good sense to proceed with a single, new reference parcel in the future.

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