# OuterPolygon

OuterPolygon[poly]

gives the outer polygon of the polygon poly.

# Details • OuterPolygon is also known as polygon outer ring.
• Typically used to decompose a polygon as a difference of simple polygons, even when the original construction of the polygon was using crossing curves etc.
• OuterPolygon is defined by the canonicalization performed in CanonicalizePolygon.
• • OuterPolygon gives a polygon of the form Polygon[{p1,p2,},{{i1,i2,},}], where pk are explicit coordinates, and ik are integer indexes referring to coordinates in the list {p1,p2,}.
• In general, the result will be a Polygon object representing a disjoint union of simple polygons.

# Examples

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## Basic Examples(1)

Get the outer polygon from a Polygon:

## Scope(6)

OuterPolygon works on polygons:

Triangle:

Rectangle:

OuterPolygon works on polygons of geographic entities:

Polygons with GeoPosition:

Polygons with GeoGridPosition:

Polygon with holes:

Polygons with disconnected components:

Polygons in :

## Properties & Relations(2)

OuterPolygon of a simple polygon is the polygon itself:

A simple polygon has the same polygon coordinates as its OuterPolygon: