ArcGIS Pro 3.4 API Reference Guide
ArcGIS.Desktop.Mapping Namespace / Map Class / SetReferenceScale Method
A double represents the reference scale of the map.
Version

SetReferenceScale Method
Updates the reference scale of the map. This method must be called on the MCT. Use QueuedTask.Run.
Syntax
public void SetReferenceScale( 
   double referenceScale
)

Parameters

referenceScale
A double represents the reference scale of the map.
Exceptions
ExceptionDescription
This method or property must be called within the lambda passed to QueuedTask.Run.
Remarks
When reference scale is set and a FeatureLayer's ScaleSymbols property is set to true, symbol size will get larger if you zoom in to a scale larger than the ReferenceScale and smaller if you zoom out to a scale smaller than the ReferenceScale.
Requirements

Target Platforms: Windows 11, Windows 10

ArcGIS Pro version: 3 or higher.
See Also