QueryFirstLastM Method (IGeometryEngine)

In This Topic

Gets the first and last defined M-values in the polyline.

Syntax

C#
Visual Basic (Declaration)

void QueryFirstLastM( 
   Polyline polyline,
   out double firstM,
   out double lastM
)

Sub QueryFirstLastM( _
   ByVal polyline As Polyline, _
   ByRef firstM As Double, _
   ByRef lastM As Double _
)

Parameters

polyline: The input polyline.
firstM: The first M-value that is not NaN.
lastM: The last M-value that is not NaN.

Return Value

The first and last defined M-values in the polyline. If the polyline is empty or all the M-values are NaN, then NaN values are returned.

Exceptions

Exception	Description
System.ArgumentNullException	Polyline is null.
System.InvalidOperationException	This geometry is not M-Aware.

Example

Get the first and last defined M-values in a polyline - QueryFirstLastM

string json = "{\"hasM\":true,\"paths\":[[[5,4,6],[6,4,5],[8,6,7]],[[0,0,1],[0,1,0],[1,1,-1],[1,0,-2]]]}";
Polyline polyline = PolylineBuilderEx.FromJson(json);

double firstM, lastM;
GeometryEngine.Instance.QueryFirstLastM(polyline, out firstM, out lastM);
// firstM = 6, lastM = -2

json = "{\"hasM\":true,\"paths\":[[[5,4,null],[6,4,5],[8,6,7]],[[0,0,1],[0,1,0],[1,1,-1],[1,0,null]]]}";
polyline = PolylineBuilderEx.FromJson(json);

GeometryEngine.Instance.QueryFirstLastM(polyline, out firstM, out lastM);
// firstM = 5, lastM = -1

json = "{\"hasM\":true,\"paths\":[[[5,4,null],[6,4,null],[8,6,null]],[[0,0,null],[0,1,null],[1,1,null],[1,0,null]]]}";
polyline = PolylineBuilderEx.FromJson(json);

GeometryEngine.Instance.QueryFirstLastM(polyline, out firstM, out lastM);
// firstM and lastM are NaN

json = "{\"hasM\":true,\"paths\":[]}";
polyline = PolylineBuilderEx.FromJson(json);

GeometryEngine.Instance.QueryFirstLastM(polyline, out firstM, out lastM);
// firstM and lastM are NaN

Requirements

Target Platforms: Windows 11, Windows 10

ArcGIS Pro version: 3.3 or higher.

Reference

IGeometryEngine Interface
IGeometryEngine Members

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