ArcGIS Pro 3.4 API Reference Guide
ArcGIS.Core.CIM Namespace / CIMMarkerPlacementOnLine Class / RelativeTo Property
Example Version

RelativeTo Property
Gets or sets the location on a line where a marker will be placed. The direction of the line is determined by the direction in which the line was digitized.
Syntax
public PlacementOnLineRelativeTo RelativeTo {get; set;}
Example
How to construct a multilayer line symbol with an arrow head on the end
//These methods must be called within the lambda passed to QueuedTask.Run
var markerTriangle = SymbolFactory.Instance.ConstructMarker(ColorFactory.Instance.RedRGB, 12, SimpleMarkerStyle.Triangle);
markerTriangle.Rotation = -90; // or -90
markerTriangle.MarkerPlacement = new CIMMarkerPlacementOnLine() { AngleToLine = true, RelativeTo = PlacementOnLineRelativeTo.LineEnd };

var lineSymbolWithArrow = new CIMLineSymbol()
{
  SymbolLayers = new CIMSymbolLayer[2] { markerTriangle,
              SymbolFactory.Instance.ConstructStroke(ColorFactory.Instance.RedRGB, 2)
          }
};
Requirements

Target Platforms: Windows 11, Windows 10

ArcGIS Pro version: 3 or higher.
See Also