Is it possible to create a buffer around neighbouring polygons, so that the new polygons do not overlap?

Preferably in QGIS but any other tool will do.

So instead of the first result I would like to obtain something similar to the second:

enter image description here

  • 1
    If you don't want your buffer to overlap, you could Dissolve the buffer polygons. However, it won't reflect your second image. – Joseph Jan 7 '16 at 12:10
  • 1
    I'd tend for some kind of raster solution, akin to this answer. – Richard Law Jan 8 '16 at 4:22
  • I don't know of a QGIS tool that could do it, but in theory you could compute the (possibly intersecting) buffers normally, and also compute the (generalized) Voronoi diagram of your polygons, and then intersect each buffered polygon with the Voronoi cell containing that polygon. The Boost C++ library has some Voronoi tools that could work, but it would be a lot of C++ glue code to write. – csd Mar 23 '17 at 21:34

If you are able to have an ArcGIS account you can do this process easily through ArcGIS Online. When creating a web map through Arc GIS Online you can use a limited amount of analysis tools. The buffer analysis tool gives you options to overlap or dissolve the buffers. From there you can export that layer as a shapefile.

For QGIS, you will first want to use the Create Buffers tool and input whatever radius and radius unit you would like. Then you will go into your geoprocessing tools and use the Dissolve tool. This will dissolve the boundaries of your buffers and basically create something that looks like one large buffer.

  • 2
    The QGIS solution does not result in the Second image! My understanding is that the two orange polygons will have the attributes of the two green polygons and are not dissolved into one big polygon – RutgerH Jun 6 '17 at 21:28

One way to do this, depending on the quality/complexity of the polygon layer, is with the following steps:

1) Extract vertices from polygons, ensuring a unique field is kept as an attribute

2) Create a voronoi from these points

3) Buffer the original polygons by the required amount

4) Subtract the buffer polygons from the voronoi

5) Recombine/dissolve the remaining voronoi polygons on the unique attribute field

When doing this in the past with slightly inconsistent datasets I've had to do additional steps to remove artefacts from within the new polygons:

  • Subtract original polygons from new layer to remove in-polygon artefacts
  • Add original polygons into new dataset
  • Recombine/dissolve again on key field

The advantage of the voronoi step (as also suggested by csd) is that it gives perpendicular boundaries, as your requirement diagram showed.

Some of these operations can take significant amounts of time though....

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.