ArcGIS Pro 3.3 API Reference Guide
ArcGIS.Core.Geometry Namespace / GeometryEngine Class / Boundary Method
Specifies the input geometry.

In This Topic
    Boundary Method (GeometryEngine)
    In This Topic
    Calculates the boundary of the input geometry.
    public Geometry Boundary( 
       Geometry geometry
    Public Function Boundary( _
       ByVal geometry As Geometry _
    ) As Geometry


    Specifies the input geometry.

    Return Value

    The geometry that represents the boundary of the input geometry. For Point - returns an empty point. For Multipoint - returns an empty point. For Envelope - returns a polyline, that bounds the envelope. For Polyline - returns a multipoint, using OGC specification (includes path endpoints, using mod 2 rule). For Polygon - returns a polyline that bounds the polygon by adding all rings of the polygon to a polyline.
    Geometry is null or empty.
    The method is not implemented for GeometryBag.
    If the input geometry is not known-simple, then the operation will be performed on a simplified copy of the geometry.

    GeometryEngine Boundary

    Determine the boundary of a multi-part Polygon
    // create a donut polygon.  Must use the PolygonBuilderEx object
    List<Coordinate2D> outerPts = new List<Coordinate2D>();
    outerPts.Add(new Coordinate2D(10.0, 10.0));
    outerPts.Add(new Coordinate2D(10.0, 20.0));
    outerPts.Add(new Coordinate2D(20.0, 20.0));
    outerPts.Add(new Coordinate2D(20.0, 10.0));
    List<Coordinate2D> innerPts = new List<Coordinate2D>();
    innerPts.Add(new Coordinate2D(13.0, 13.0));
    innerPts.Add(new Coordinate2D(17.0, 13.0));
    innerPts.Add(new Coordinate2D(17.0, 17.0));
    innerPts.Add(new Coordinate2D(13.0, 17.0));
    Polygon donut = null;
    // add the outer points
    PolygonBuilderEx pb = new PolygonBuilderEx(outerPts);
    // add the inner points (note they are defined anticlockwise)
    // get the polygon
    donut = pb.ToGeometry();
    // get the boundary 
    Geometry g = GeometryEngine.Instance.Boundary(donut);
    Polyline boundary = g as Polyline;

    Target Platforms: Windows 11, Windows 10

    ArcGIS Pro version: 3 or higher.
    See Also