Assign a route identifier field

A route identifier field uniquely identifies each route in a feature class. Assigning a route identifier field is not required when working with routes; however, it saves you from having to set the route identifier field each time you use the linear referencing geoprocessing tools. When you assign a field as the route identifier, the selection is saved with the layer.

Assign a route identifier field to a layer

The route identifier field can be any numeric or character field in a route feature class. To assign a route identifier field, the active map must contain an m-aware linear feature.

To assign a route identifier field to a layer, complete the following steps:

  1. Click the contextual Linear Referencing tab.
  2. In the Route Identifier group, click the Layer Name drop-down arrow and select the layer of interest.
  3. Click the Route Id Field drop-down arrow and select the field of interest.

    The layer now has an assigned route identifier field.


    Since assigning a route identifier is layer based, if you add another layer for the same feature class after a route identifier is assigned, the new layer will not have the selection.

  4. In the table of contents, with the layer selected from step 3, click the Tools drop-down arrow in the Analysis group on the Linear Referencing tab, and click the Calibrate Routes, Locate Features Along Routes, Make Route Event Layer, or Transform Route Events geoprocessing tool.

    The Geoprocessing pane opens with the route feature class and route identifier field information automatically filled in.