Merging centerlines

The Merge Centerlines tool is one of the centerline editing tools available in Esri Roads and Highways. This tool helps reduce the segmentation in the centerlines by merging them together on the basis of the common route ID shared by them.

You should not use the Merge tool on the ArcMap Editor toolbar to merge centerlines. Instead, you should use the Merge Centerlines tool on the Roads And Highways Editing toolbar. This tool ensures that when centerlines are merged, the source centerline's association to routes in all networks across all time is maintained and that the centerline's segmentation resulting from route definitions is honored.

Network	Route	Centerline before merge	Centerline remaining after merge
A	1001	1, 2, 3, 4	1, 4
B	2001	1, 2, 3	1

Centerlines before merge

Centerlines after merge

You can see that the Merge Centerlines tool reduces segmentation in the data, maintaining existing route relationships to the edited centerline. Use the following steps to use the Merge Centerlines tool.

Steps:

1. Start ArcMap and add the centerline and the network layers to the map.
2. Start an edit session and zoom to the centerline you want to merge.

   For more information on how to start an edit session, see About edit sessions.

3. Use the Edit tool on the Editor toolbar to select the centerlines to merge.

   The Esri Roads and Highways Merge Centerlines tool will merge centerlines that are selected in ArcMap. You can use any of the ArcMap selection tools to select centerlines to merge.

   The selected centerlines are highlighted in cyan.

4. Click the Merge Centerlines button on the Roads And Highways Editing toolbar.

   Centerlines can only be merged to the granularity of route definitions. If some centerlines don't merge, it is likely because there is a route in a network or time span that disallows it. This behavior is intended.

   The centerlines are now merged on the basis on their common route ID.