ArcGIS Pro 2.7 API Reference Guide
Domain Property (SpatialReference)

ArcGIS.Core.Geometry Namespace > SpatialReference Class : Domain Property
Gets the square domain extent of the spatial reference.
Syntax
public Envelope Domain {get;}
Public ReadOnly Property Domain As Envelope
Remarks
The domain extent is different than the valid area of a coordinate system. The domain extent is an arbitrary square used to delimit valid coordinates for a spatial reference system and determine their resolution. It is possible that the domain extent is larger than the usable area of a coordinate system (a UTM zone, for example).
Requirements

Target Platforms: Windows 10, Windows 8.1

See Also

Reference

SpatialReference Class
SpatialReference Members