Sub (difference)

syntax

sub(polygon_data_itemA, polygon_data_itemB)
polygon_data_itemA - polygon_data_itemB

definition

sub(polygon_data_itemA, polygon_data_itemB) or polygon_data_itemA

polygon_data_itemB results in a new polygon data-item with the difference of the two arguments: polygon_data_itemA and polygon_data_itemB

The left part of the figure illustrates the arguments: polygon_data_itemA and polygon_data_itemB.

The resulting polygon (right side of the image) is the original square (polygon_data_itemA) minus the district polygon_data_itemB.

description

The sub-function can, for example, be used to create a mask polygon.

applies to

data items polygon_data_itemA and polygon_data_itemB with an ipoint or spoint value-type. A dpoint or fpoint is also allowed since version 15.6.0.

conditions

The composition type of the argument items needs to be polygon.
The domain of the arguments must match or be void.

since version

7.112 15.6.0 (in case of floating point coordinates)

example

parameter<ipoint> geometry (poly) := square/geometry[0] - union_polygon/geometry;