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I'm looking for a simple way to generate contiguous "territories" from sets of points. Say, points A, B and C are in territory 1, and D, E and F are in territory 2, then generate polygons that lie roughly halfway between the two sets. No need to take into account routing or anything like that.

In the browser with Leaflet would be great, but failing that, GDAL or QGIS.

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    You want a Thiessen or Voronoi diagram followed by dissolve by attributes. I'm fairly sure if you Google Voronoi and QGIS you'll get a few answers. – Michael Stimson Nov 13 '14 at 4:02
  • ^ This comment contained the answer I was looking for. – LazerSharks Aug 31 '16 at 15:57
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First create a Voronoi diagram around the given points, then apply a dissolve by attribute.

To create Voronoi polygons in QGIS there's a tutorial here use Vector::Geometry Tools::Voronoi Polygons. This produces one polygon per input point; the attributes are copied to the polygons which is important later.

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Dissolve the Voronoi polygons using the territory attribute from the points to form territories. Vector::Geoprocessing Tools::Dissolve

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  • Ah, thanks. I didn't see it as just merging Voronoi polygons. Is there a distinction between "dissolving" polygons and some other way of combining polygons? – Steve Bennett Nov 13 '14 at 6:10
  • There are ways to aggregate polygons that simplify the boundary or merge isolated instances I'm not sure how many of these are available to QGIS, there may be plugins that help with more advanced operations. – Michael Stimson Nov 16 '14 at 23:13

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