I am working with a large river network polyline shapefile. I am trying to calculate a dendritic connectivity index using a point shapefile representing locations.

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The river network shapefile has a large number of rows/individual lines that I merged into one row/line. I want to split this river network into distinct segments where a dam intersects it, where I would be able to calculate the length of each of these segments (fragments). I have tried the "Split Line at Point" tool and this simply split the river network at each vertex, not each point despite it being a single feature.

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    What GIS software are you using? – PolyGeo Nov 13 '18 at 19:26
  • I don't think your approach will work, if you are using ArcMap, as that tool will planarize the output and return the network back as the original edges but also split at the Dams. Are you looking to compute the total distance between the Dams or actually extract out the sub-networks for visualisation? – Hornbydd Nov 13 '18 at 22:16
  • I'm using ArcMap, but will eventually move into R. I am trying to calculate individual distances of the subnetworks, yes. Is there any way to do this? – Ecostrider Nov 14 '18 at 2:08
  • Have a look at RivEX it has a tool for identifying nearest upstream sites. Once you have transferred upstream distance to the dams then you can work out the sub-network lengths. – Hornbydd Nov 14 '18 at 11:12

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