I am on the project to identify the specific roads that are more frequently used than others. With the network shapefiles (OS ITN), origins and destinations (OD) points, route was created for each set of OD (Closest facility tool). What I want to do next is to identify the roads that are used for more than one routes; for instance, assuming that there are 5 people, each of them departs from different point (origin) to get to the point A (destination), but there are some roads that all of them need to use along the way. In other words, I want to extract the lines that "overlapped". As an experiment, I created 3 routes separately and tried to extract overlapped features using overlay tool - intersect - but it didn't work. I tried converting it to Raster and did "Overlay sum" but didn't work.

If anyone can suggest the way to solve my problem, that would be really helpful.

  • What you describe sounds like a line on line overlay so I think you should investigate the linear referencing tool for overlaying linear events. – PolyGeo May 7 '14 at 15:12

So you have run your Closest Facility solver and get a couple of Routes in the Routes sublayer of the network analysis layer.

You might see something like this (where squares are incidents and the circle is the facility); I have used slight offset for the routes so it would be possible to see that they overlap:

enter image description here

Now you want to extract just those parts segments that touch each other (or in other words intersect). Since each route is represented by just one feature, we would want to split it up into multiple line segments. This can be done by using the Split line at vertices GP tool. After that we can run Intersect GP tool by providing as input the result of the Split line at vertices GP tool run.

This will give us features (lines with the attributes of the Routes sublayer preserved) that intersect (pink area dashed). If you want to go further to select street segments that intersect those pieces of Routes we have obtained, you could just use Select By Attributes in ArcMap to see what Routes' parts intersect underluying street network edges.

enter image description here

  • Where is the option to offset overlapping routes? – Maksim Oct 15 '14 at 13:30

Network analyst will yield route layers. If you want to intersect (intersect_analysis was the right tool) them you need to convert to a feature clas first (using select data and create features)

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