area - ObjectVision/GeoDMS GitHub Wiki

Geometric functions area

• area(polygon_data_item, valuesunit)

area(polygon_data_item, valuesunit) calculates the surface of the polygon_data_item argument, in the image the green hedged area.

The resulting values unit is configured as second argument.

The resulting area values need to be positive, if the values are negative it means the order of points in the polygon geometry is not according to the following rules:

The order of points in a sequence needs to be clockwise for exterior bounds and counter clockwise for holes in polygons (right-hand-rule)

• data item polygon_data_item with fpoint or dpoint value type and composition type polygon.

The metric of the values unit argument must match with the square of the metric of the coordinates in the coordinate system.

attribute<m2> surface (district) := area(district/geometry, m2);

domain district, nr of rows = 3