I have a bundle of links in 'some' networks. I need to find out which ones are connected to each other i.e. I need to find out which links are not connected to the 'main' network.

I have been working on a flood fill recursive method, which effectively goes from link to link, finding out which ones are connected, and recursively doing the same. But the numbers are quite high, and my machine just bailed, so I wondered if there were other, better, or more efficient, ways of doing this.

Using arcpy

Thanks in advance

  • 1
    Overview of algorithms to find connected components of graphs: en.wikipedia.org/wiki/…. Open source solution (I haven't benchmarked it to establish what size problems it handles): igraph.sourceforge.net/doc/R/clusters.html.
    – whuber
    Mar 6, 2013 at 21:31
  • 1
    thnx - struggling, but it's been a bad week...
    – Hairy
    Mar 6, 2013 at 22:10
  • Thats not really going to work for me. I have just had a look at FME and it looks like they have a networkconnector in there.
    – Hairy
    Mar 8, 2013 at 11:49

2 Answers 2


I used FME 2013 NetworkTopologyCalculator. Phenominal, took 4 seconds...


I usually use Esri geometric networks for testing connectivity of road segments when checking the transportation networks. There are some tools for tracing geometric network available from the Utility Network Analyst toolbar in ArcMap (you will be able to find disconnected segments, i.e., those ones from which you cannot reach all other network segments) as well as GP tools which you may also call from arcpy if you wish. I believe these tools will let you get the work done without crashing the machine. I've run these tools on 2 mil.+ segments network and it worked fine.

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