ArcGIS Pro 3.4 API Reference Guide
ArcGIS.Desktop.Mapping Namespace / FeatureLayer Class / ArePreviousObservationsVisible Property
Example Version

ArePreviousObservationsVisible Property
Gets whether Previous Observations will be displayed.
Syntax
public bool ArePreviousObservationsVisible {get;}
Example
Check Previous Observation and Track Line Visibility
//The layer must be track aware and spatial for these settings
//to have an effect
if (streamLayer.TrackType != TrackType.Spatial)
  return;
//Must be on QueuedTask
if (!streamLayer.AreTrackLinesVisible)
  streamLayer.SetTrackLinesVisibility(true);
if (!streamLayer.ArePreviousObservationsVisible)
  streamLayer.SetPreviousObservationsVisibility(true);
Make Track Lines and Previous Observations Visible
//The layer must be track aware and spatial for these settings
//to have an effect
if (streamLayer.TrackType != TrackType.Spatial)
  return;

//Must be on QueuedTask

//Note: Setting PreviousObservationsCount larger than the 
//"SetExpirationMaxCount()" has no effect
streamLayer.SetPreviousObservationsCount(6);
if (!streamLayer.AreTrackLinesVisible)
  streamLayer.SetTrackLinesVisibility(true);
if (!streamLayer.ArePreviousObservationsVisible)
  streamLayer.SetPreviousObservationsVisibility(true);
Requirements

Target Platforms: Windows 11, Windows 10

ArcGIS Pro version: 3 or higher.
See Also