Polygon_connectivity

geometric-functions polygon_connectivity

syntax

  • polygon_connectivity(polygon_data_item)

definition

polygon_connectivity(polygon_data_item) results in a new uint32 domain-unit with one entry for each ‘connection’ in the polygon_data_item argument.

A ‘connection’ is defined as two polygons having at least one common interior point.

description

The function results in an F1 and F2 attribute with relations to the domain-unit of the polygon_data_item attribute.

The relations indicate which connections exists, each connection only occurs once (a connection between polygon 0 and 1 only occurs as F1: 0 and F2: 1 and not vice versa).

Use the multiply operator for polygons to calculate the overlap between connected polygons.

applies to

attribute polygon_data_item with an ipoint or spoint value-type.

conditions

  1. The composition type type of the polygon_data_item argument needs to be polygon.
  2. The order of the points in polygon_data_item needs to be clockwise for exterior bounds and counter clockwise for holes in polygons (right-hand-rule).

since version

7.135

example 

unit<uint32> connection := polygon_connectivity(district/geometry);
F1 F2
0 3
0 5
0 6
1 2
1 3
1 6
2 3
2 4
2 6
3 4
3 5
3 6
4 5

domain connection, nr of rows = 13

see also