how to calculate M value in a polyline(ZM)?

[peterzhou]

i create a polyline(ZM) which has x,y,z value, but M is NaN. how can i get the M value?

[FilipKrál]

You can 'populate' the M values by the process of Linear Referencing , which you better read up about in the help.

Specifically the topics on creating route feature class is probably what you need.

[peterzhou]

i use Linear Referencing Tools>>Create Routes to create a new polyline with M values, but the M values count X,Y and igore the Z values, that means the M values are 2D polyline values.

[RichardFairhurst]

All of the tools Esri provides only handle the creation of 2D measures.  The Add-In I designed was primarily intended to create 3D measures on XYZ polylines with different options for handling unit conversions, unit offsets, polyline gaps, measure orientations that increase with or against the digitized line direction, etc,  These options are intended to emulate the Create Route tool options without having to create a new feature class.

The Add-In has no problem generating 2D measures using any of these options on existing XYZ polylines without creating a new feature class as well.  However, there are several alternative methods for creating and maintaining 2D measures with existing Esri tools, including the Create Route tool.

[RichardFairhurst · Accepted solution]

Please check out the Add-In you can download from this post that can create 3D or 2D measures based on line length for features in a feature class that uses a Projected Spatial Reference with linear XYZ coordinates like meters or feet.  If your layer is in a Geographic Spatial Reference with radial XY coordinate values like degrees in latitude and longitude the tool does not support that.

[peterzhou]

Thanks Richard, it works good!