I have a shapefile table of property parcels that are polygons. I am looking to group these parcels by subdivision. If I know which parcels belong in which subdivsion, is there a way to generate a polygon that is the sum of other polygons in shapefile format so that I do not have draw out each subdivision?

  • 3
    This sounds like a Dissolve. – PolyGeo Jul 5 '17 at 21:57
  • So if I add a field that I call the Subdvision_ID in the parcel shapefile table, I will be able to dissolve the polygons based off that field? – Mwspencer Jul 5 '17 at 22:00
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    That's correct. However, it's unlikely that you will end up with the exact subdivision boundary. You may need to apply a convex hull or even do some manual editing to get the actual boundary. – Fezter Jul 5 '17 at 22:06
  • As @Fezter says Dissolve may not take you all the way unless your roads within the subdivision are also coded with its ID. – PolyGeo Jul 5 '17 at 22:28
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    Should you have an advanced license you could dissolve by subdivision_id (BTW that field name is too long for a shapefile) then feature to point, generate Thiessen polygons and dissolve the Thiessen polygons by subdivision_id.. it won't be perfect but will at least have no gaps. It is important to have parcels outside your target subdivision with empty ('' or 0) subdivision_id to constrain the Thiessen polygons or they will extend to the boundary of the overall extent which is probably not what you want, then remove these polygons before or after 2nd dissolve. – Michael Stimson Jul 5 '17 at 22:38

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