ArcGIS Pro 3.4 API Reference Guide
ArcGIS.Desktop.Mapping Namespace / FeatureLayer Class / SetPreviousObservationsVisibility Method
Indicates whether previous observations should be displayed.
Example Version

SetPreviousObservationsVisibility Method
Specifies whether to display previous observations or not.
Syntax
public void SetPreviousObservationsVisibility( 
   bool previousObservationsVisible
)

Parameters

previousObservationsVisible
Indicates whether previous observations should be displayed.
Exceptions
ExceptionDescription
This method or property must be called within the lambda passed to QueuedTask.Run.
This feature layer does not support tracks.
Remarks
Non-track aware layers will throw a System.InvalidOperationException
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