ArcGIS Pro 2.8 API Reference Guide
Union Method (EnvelopeBuilder)
Example 

ArcGIS.Core.Geometry Namespace > EnvelopeBuilder Class : Union Method
The envelope to union with.
Unions the input Envelope with the EnvelopeBuilder. This method must be called on the MCT. Use QueuedTask.Run.
Syntax
public Envelope Union( 
   Envelope envelope
)
Public Function Union( _
   ByVal envelope As Envelope _
) As Envelope

Parameters

envelope
The envelope to union with.

Return Value

Envelope containing both envelopes.
Exceptions
ExceptionDescription
This method or property must be called within the lambda passed to QueuedTask.Run.
Remarks
Sets the EnvelopeBuilder equal to the union of the base Envelope and the input Envelope. The XMin and YMin of the resulting EnvelopeBuilder is the minimum XMin and YMin respectively between the base and input Envelopes, and the XMax and YMax of the resulting Envelope is the maximum XMax and YMax respectively between the base and input Envelopes.

Union

Example
// use the convenience builders - don't need to run on the MCT.
Envelope env1 = EnvelopeBuilder.CreateEnvelope(0, 0, 1, 1, SpatialReferences.WGS84);
Envelope env2 = EnvelopeBuilder.CreateEnvelope(0.5, 0.5, 1.5, 1.5, SpatialReferences.WGS84);

Envelope env3 = env1.Union(env2);

double area = env3.Area;
double depth = env3.Depth;
double height = env3.Height;
double width = env3.Width;
double len = env3.Length;

MapPoint centerPt = env3.Center;
Coordinate2D coord = env3.CenterCoordinate;

bool isEmpty = env3.IsEmpty;
int pointCount = env3.PointCount;

// coordinates
//env3.XMin, env3.XMax, env3.YMin, env3.YMax
//env3.ZMin, env3.ZMax, env3.MMin, env3.MMax

bool isEqual = env1.IsEqual(env2);    // false


// or use the builder constructor - need to run on the MCT.
using (var builder = new EnvelopeBuilder(0, 0, 1, 1, SpatialReferences.WGS84))
{
  env3 = builder.Union(env2);     // builder is updated to the result
  depth = builder.Depth;
  height = builder.Height;
  width = builder.Width;

  centerPt = builder.Center;
  coord = builder.CenterCoordinate;

  isEmpty = builder.IsEmpty;
}


// or use the builderEx constructors = don't need to run on the MCT.
EnvelopeBuilderEx builderEx = new EnvelopeBuilderEx(0, 0, 1, 1, SpatialReferences.WGS84);
builderEx.Union(env2);      // builder is updated to the result

depth = builderEx.Depth;
height = builderEx.Height;
width = builderEx.Width;

centerPt = builderEx.Center;
coord = builderEx.CenterCoordinate;

isEmpty = builderEx.IsEmpty;

env3 = builderEx.ToGeometry() as Envelope;
Requirements

Target Platforms: Windows 10, Windows 8.1

See Also

Reference

EnvelopeBuilder Class
EnvelopeBuilder Members