cgal_polygon_connectivity

Geometric functions > cgal_polygon_connectivity

syntax

cgal_polygon_connectivity(polygon_data_item)

description

cgal_polygon_connectivity(polygon_data_item) finds all pairs of adjacent (touching or overlapping) polygons in the polygon_data_item and returns them as a new domain.

The result is a new domain unit (uint32) where each entry represents one adjacency relationship between two polygons. Two sub-attributes relate each entry back to the first and second polygon in the pair.

The cgal_ prefix of the function name indicates that the implementation of the operator uses CGAL, which provides exact predicates and exact constructions for maximum numerical precision.

applies to

attribute polygon_data_item with a polygon value type

conditions

The composition type of the polygon_data_item needs to be polygon.

result

The result is a container (new domain unit of type uint32) with:

F1: relation to the domain of polygon_data_item for the first polygon in each adjacent pair
F2: relation to the domain of polygon_data_item for the second polygon in each adjacent pair

since version

14.0

example

unit<uint32> adjacency := cgal_polygon_connectivity(district/geometry)
{
    attribute<district> F1;
    attribute<district> F2;
}