GeodesicLength(Geometry,LinearUnit) Method

C#
Visual Basic (Declaration)

public double GeodesicLength( 
   Geometry geometry,
   LinearUnit lengthUnit
)

Public Overloads Function GeodesicLength( _
   ByVal geometry As Geometry, _
   ByVal lengthUnit As LinearUnit _
) As Double

Parameters

geometry: The input geometry. Cannot be null and its spatial reference cannot be null.
lengthUnit

Return Value

The calculated geodesic length in outputUnits. If outputUnits is null, then the length is in meters.

If the geometry is empty, then zero is returned.

Exception	Description
System.ArgumentNullException	Geometry is null.
System.NotImplementedException	The method is not implemented for GeometryBag or Multipatch.
System.NotImplementedException	Spatial reference of geometryis an image coordinate system.

Geodesic length is calculated by using only the vertices of the geometry and defining the segments between the points as geodesic segments independent of the actual shape of the geometry. A geodesic segment is the shortest path between two points on an ellipsoid. For example, if you have a closed polyline with only two vertices that represents the equator, the length returned will be zero.

C#

var polyline = PolylineBuilder.CreatePolyline(new[]
{
    MapPointBuilder.CreateMapPoint(-10018754.1713946, 10018754.1713946),
    MapPointBuilder.CreateMapPoint(10018754.1713946, 10018754.1713946)
}, SpatialReferences.WebMercator);

var length = GeometryEngine.Instance.GeodesicLength(polyline);
// length is approx 5243784.5551844323 in meters

length = GeometryEngine.Instance.GeodesicLength(polyline, LinearUnit.Miles);
// length is approx 3258.33666089067 in miles

var polyline2 = GeometryEngine.Instance.Project(polyline, SpatialReferences.WGS84);
length = GeometryEngine.Instance.GeodesicLength(polyline2);
// length is approx 5243784.55518443 in meters after projecting

Target Platforms: Windows 11, Windows 10, Windows 8.1

Reference

GeometryEngine Class
GeometryEngine Members
Overload List