Points and the 4-hectare rule: when a plot needs a polygon
A plot can be described by a single point only if it is 4 hectares or smaller. Above that, the EU Information System expects a polygon, except for cattle.
What the EU documentation says
- The FAQ and the DDS API reference: polygons are required for plots of land greater than 4 hectares, except for cattle, where point coordinates for the establishment suffice.
- The Validation Rules: when a point is provided, the area is mandatory. If no value is given, the system enters 4 (ha) by default. If the commodity is not cattle and the value is higher than 4 ha, the system raises an error. When provided, the area must be at least 0.0001 ha.
- The GeoJSON File Description: the optional
Areaproperty is the area in hectares of a Point geometry, and if it isn't provided it's set to 4 ha. It also warns that"Area": "3"(a number in quotes) is read as 0, because a quoted value isn't recognized as a number.
What this means for a plot file
- A 2.5 ha cocoa plot can be a Point with
"Area": 2.5. - A 7 ha coffee plot needs a Polygon (or MultiPolygon). A Point with
"Area": 7is an error. - A point with no Area is treated as 4 ha. That passes, but it may misstate the plot size.
"Area": 0, or"Area": "2.5"(text, read as 0), falls below the 0.0001 ha minimum.
The EU page also suggests using single points for plots under 4 hectares, rather than polygons, as a way to keep file size down; see file size limit.
How to fix it
- For any point whose Area is over 4, map the plot boundary and replace the point with a polygon.
- Write Area as a number without quotes:
"Area": 2.5. - Use hectares, not square metres or acres. 25,000 m² is 2.5 ha; an Area of 25000 would be read as 25,000 ha.
- If a point has no measured area, consider recording one rather than relying on the 4 ha default.
What the Plot File Checker does
- Point with Area over 4 ha: error (the message mentions the cattle exception).
- Point with no Area: info, noting the 4 ha default.
- Point with Area under 0.0001 ha, including 0: error.
- Area written as text: warning, turned into a number in the fixed file.
- For polygons, an Area that differs from the computed area by more than 25% and more than 0.5 ha: warning. Polygons under 100 m² or over 5,000 ha are also flagged for a second look.