I have road segments and want to convert them into one link (intersection to intersection). Image 1 shows the segments.

enter image description here

The biggest issue is that each link has traffic volume and when converted to links (one single line from one intersection to the other) the value of traffic volume for the link needs to be the mean of individual traffic volumes.

It should come out as one segment with the mean of all the volumes between two intersections.

enter image description here

  • Is there a segmentID on the road features such that all features on the same segment have the same ID? Should the mean be weighted by length? Dec 13, 2019 at 21:30
  • the mean should not be weighted by length. Unfortunately, the only common ID they have is the route name. so two or many links would have the same route name but are separated by an intersection. Dec 13, 2019 at 21:37
  • This is a very common, but nontrivial, step in preparing GIS data for HPMS. A search for hpms gis segment merge turns up this Dec 13, 2019 at 21:43
  • @KirkKuykendall Does this specify the solution to the problem? I went through it... is there a specific page number of methodology you are pointing me towards? Dec 13, 2019 at 22:17
  • I don't know of any high level description, if you want code solution, maybe look here. In case you have to deal with gaps. gis.stackexchange.com/q/119159/59 Dec 14, 2019 at 3:16

1 Answer 1


This can be mostly resolved with a simple dissolve.

This is your starting situation:

network Line direction is indicated by arrow, lines are labelled with volume and green points are the end nodes of a line

If you ran this through the Dissolve tool as set up as below:


You end up with this which for most of the network is exactly what you want BUT...


Lines colour coded by polyline ID, red label is mean volume.

If you read the help file for the Dissolve tool for the Unsplit lines parameter it says it dissolves when only 2 are joined. I highlight to end points in blue which may be a junction and the third road is simply not shown for what ever reason so it erroneously dissolves it. But if this really was a loop in the network then the mean volume would be OK.

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