Centroid_or_mid

syntax

centroid_or_mid(polygon_data_item)

definition

centroid_or_mid(polygon_data_item) results in a Point Data item with

the Centroid if it is located in the Polygon
or else the mid of the polygon_dataitem Argument. The mid of a polygon is calculated as the middle point of the coordinates of the polygon in such a way that it is always located within the polygon. See here for a description.

description

The centroid_or_mid function results in the centroid if it is located within the polygon or else in the mid of the polygon. This means the result of the centroid_or_mid is always located within the polygon, or at its border such that Point_in_polygon would return true.

In the image above the centroid is not located within the polygon. The centroid_or_mid function will still result in a point within the polygon.

applies to

data item polygon_dataitem with fpoint or dpoint Value type and composition type polygon.

example

attribute<point_rd> centroid_or_mid (district) := centroid_or_mid(district/geometry);

district/geometry	centroid_or_mid
{21: xy(113810; 403025) …	xy(113049; 402955)
{17: xy(113269; 400990) …	xy(112704; 401159)
{19: xy(115099; 401238) …	xy(114017; 401268)

domain district, nr of rows = 3