ArcGIS Pro 2.7 API Reference Guide
GeodesicSector Method (IGeometryEngine)
Example 

ArcGIS.Core.Geometry Namespace > IGeometryEngine Interface : GeodesicSector Method
The geodesic sector parameter that describes how to draw the geodesic sector.
The spatial reference of the sector.
The function returns a piecewise approximation of a geodesic ellipse (or geodesic circle, if SemiAxis1Length = SemiAxis2Length). Constructs a geodesic ellipse centered on the specified point. If this method is used to generate a polygon or a polyline, the result may have more than one part, depending on the size of the sector and its position relative to the horizon of the coordinate system. When the method generates a polyline or a multipoint, the result vertices lie on the boundary of the ellipse. When a polygon is generated, the interior of the polygon is the interior of the sector, however the boundary of the polygon may contain segments from the spatial reference horizon, or from the GCS extent.
Syntax

Parameters

parameter
The geodesic sector parameter that describes how to draw the geodesic sector.
spatialReference
The spatial reference of the sector.

Return Value

The geometry that contains sector of the geodesic ellipse.
Exceptions
ExceptionDescription
Only Polygon, Polyline and Multipoint are supported for GeodesicSectorParameter.OutGeometryType.
Either parameter or spatialReference is null.
The spatial reference is an image coordinate system.
Example
GeodesicSectorParameter param = new GeodesicSectorParameter();
param.ArcVertexCount = 50;
param.AxisDirection = Math.PI / 4;
param.Center = new Coordinate2D(0, 0);
param.LinearUnit = LinearUnit.Meters;
param.OutGeometryType = GeometryType.Polygon;
param.RadiusVertexCount = 10;
param.SectorAngle = 5 * Math.PI / 3;
param.SemiAxis1Length = 100000;
param.SemiAxis2Length = 20000;
param.StartDirection = 11 * Math.PI / 6;

Geometry geometry = GeometryEngine.Instance.GeodesicSector(param, SpatialReferences.WGS84);
// geometry.IsEmpty = false

Polygon polygon = geometry as Polygon;
// polygon.PointCount = 68
// polygon.PartCount = 1
Requirements

Target Platforms: Windows 10, Windows 8.1

See Also

Reference

IGeometryEngine Interface
IGeometryEngine Members