IsExteriorRing(Int32) Method

In This Topic

Determines if the specified part of this polygon is an exterior ring.

Syntax

C#
Visual Basic (Declaration)

public bool IsExteriorRing( 
   int index
)

Public Function IsExteriorRing( _
   ByVal index As Integer _
) As Boolean

Parameters

index: The part index.

Return Value

A boolean indicating if the part is an exterior ring.

Exceptions

Exception	Description
System.ArgumentOutOfRangeException	The index is negative or is greater than or equal to the number of parts in this polygon.

Remarks

An exterior ring is a part that is oriented clockwise.

Example

Get the exterior rings of a polygon - polygon.GetExteriorRing

public void GetExteriorRings(Polygon inputPolygon)
{
  if (inputPolygon == null || inputPolygon.IsEmpty)
    return;

  // polygon part count
  int partCount = inputPolygon.PartCount;
  // polygon exterior ring count
  int numExtRings = inputPolygon.ExteriorRingCount;
  // get set of exterior rings for the polygon
  IList<Polygon> extRings = inputPolygon.GetExteriorRings();

  // test each part for "exterior ring"
  for (int idx = 0; idx < partCount; idx++)
  {
    bool isExteriorRing = inputPolygon.IsExteriorRing(idx);
    var ring = inputPolygon.GetExteriorRing(idx);
  }
}

Requirements

Target Platforms: Windows 11, Windows 10, Windows 8.1

Reference

Polygon Class
Polygon Members

Send feedback