I am trying to split a map of an island into attribute (primary substation) areas in ArcGIS Pro. I have network locations (lines) which I have split into primary substations (as shown by the image below) on top of a polygon which is the total area of the island.

I was wondering if there is a way that the polygon can be split to give the areas that the lines distribute to. So that there would be a blue area to the north, pink in the centre, purple to the south etc. There are some lines that overlap into another primary substation area so not sure if these can be ignored. Ideally I would like the polygons generated to be touching so that there are no blank areas.

If the polygon can not be split this way is it possible to generate new polygons within the island polygon, but again without blank areas between them.

Network map of island

  • Split it manually by editing
    – Bera
    Commented Feb 16, 2021 at 14:36
  • By drawling lines? I did think this but wondered if there was a more accurate and quicker way!
    – EllisR8
    Commented Feb 16, 2021 at 14:42

1 Answer 1


An alternative repeatable process is to using the Spatial Analyst tool Euclidean Allocation

  1. Convert you vector network dataset into a raster using the Polyline to Raster tool. The value field should be the field that is grouping your polylines into their respective sub-networks, i.e. the field you are colour coding your data by. Use a sensible cell size, I used in my example below 50m.
  2. Use this raster in the Euclidean Allocation tool. Make sure you set the environment setting MASK to the isle of Wight polygon layer. A raster is created as shown below. All cells are allocated the nearest network ID.
  3. If required you can convert the allocation raster into a polygon dataset.


  • Hi @Hornbydd , thanks for getting back to me. It looks exactly like what I want! However, the polyline to raster tool keeps failing. I have tried using different cell sizes but with no luck! Any idea why this might be? Thanks
    – EllisR8
    Commented Feb 19, 2021 at 11:49
  • @EllisR8 - No! You need to set up a new question about that, we don't know anything about what format it is, how you are running the polyline to raster tool, coordinate systems, although one would expect it to be BNG. Have you got overlaps, geometry issues, where its stored etc etc... You don't even say what the error is...
    – Hornbydd
    Commented Feb 19, 2021 at 12:37

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