ArcGIS Pro 2.6 API Reference Guide
ShapePreservingArea Method (IGeometryEngine)
Example 

ArcGIS.Core.Geometry Namespace > IGeometryEngine Interface : ShapePreservingArea Method
The input geometry.
Calculates the area of the geometry on the surface of the Earth ellipsoid. This method preserves the shape of the geometry in its coordinate system.
Syntax
double ShapePreservingArea( 
   Geometry geometry
)
Function ShapePreservingArea( _
   ByVal geometry As Geometry _
) As Double

Parameters

geometry
The input geometry.

Return Value

Area of the geometry in square meters.
Exceptions
ExceptionDescription
Geometry is null or empty.
The method is not implemented for GeometryBag or Multipatch.
Geometry is missing a spatial reference.
Spatial reference of geometryis an image coordinate system.
Example
// pt
MapPoint pt = MapPointBuilder.CreateMapPoint(1.0, 3.0, SpatialReferences.WebMercator);
double area = GeometryEngine.Instance.ShapePreservingArea(pt);         // area = 0

List<MapPoint> pts = new List<MapPoint>();
pts.Add(MapPointBuilder.CreateMapPoint(1.0, 1.0, 3.0));
pts.Add(MapPointBuilder.CreateMapPoint(1.0, 3.0, 3.0));
pts.Add(MapPointBuilder.CreateMapPoint(3, 3, 3.0));
pts.Add(MapPointBuilder.CreateMapPoint(3.0, 1.0, 3.0));

// multipoint
Multipoint mPt = MultipointBuilder.CreateMultipoint(pts);
area = GeometryEngine.Instance.ShapePreservingArea(mPt);               // area = 0

// polyline
Polyline polyline = PolylineBuilder.CreatePolyline(pts);
area = GeometryEngine.Instance.ShapePreservingArea(polyline);          // area = 0

// polygon
Polygon polygon = PolygonBuilder.CreatePolygon(pts, SpatialReferences.WGS84);
area = GeometryEngine.Instance.ShapePreservingArea(polygon);

polygon = PolygonBuilder.CreatePolygon(pts, SpatialReferences.WebMercator);
area = GeometryEngine.Instance.ShapePreservingArea(polygon);
Requirements

Target Platforms: Windows 10, Windows 8.1, Windows 7

See Also

Reference

IGeometryEngine Interface
IGeometryEngine Members