Given a set of polygons of property boundary's where there is a field "Network" which shows us which network a property is in, I need to create a tight boundary for each network -it can be multipart as there will be gaps.

My workflow which mostly works is to buffer by 35m and allow "Dissolve result" and then convert to single part.

This gives me something like the following enter image description here

Which is close but on the outer edge the dark boundaries (which is the 35m buffer) shouldn't be there, except for the red areas below where it's just internal overlapping boundaries.

enter image description here

I have tried to clip this by the property boundaries in the network but this then re-adds all the small gaps over the roads etc.

I have tried the new boundary tool and the minimum bounding geometry tool but the result is as follows for both. enter image description here

I also tried polygon-to line-to point and then Delaunay triangulation and finally dissolve all polygons in the network but this is not maintain the boundary or the required gaps as well as the buffer-dissolve method.

Any suggestions on what else I can try?

  • What if you buffer the first attempt by -35 meters. Should bring it back in line to before buffering. Oct 23, 2019 at 9:08
  • is this not a union by network and then a dissolve to remove the internal boundaries?
    – Ian Turton
    Oct 23, 2019 at 9:53
  • @HeikkiVesanto -yes that comes really close. Hopefully this should suffice.
    – GeorgeC
    Oct 23, 2019 at 11:29
  • @IanTurton - i just tried this and it retains the boundaries when there's a road or some other small feature between properties. We don't want these but just the service area without any other connected properties being included.
    – GeorgeC
    Oct 23, 2019 at 11:31
  • Try the concave hull tool.
    – csk
    Oct 23, 2019 at 18:32

1 Answer 1


What if you buffer the first attempt by -35 meters. Should bring it back in line to before buffering.

Not perfect, but a working approximation.

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