9

I have an input point layer that is grouped into clusters, so I want to have each cluster of points converted into polygon.

This question (How to convert a set of points to a polygon based on a specific field in QGIS) seems to come close to what I wanted by it hasn't been answered.

So basically, I need an algorithm in QGIS that will convert each cluster of points (based on attribute field) as seen below into a polygons?

enter image description here

I have tried 'Point2One' plugin and it gave me wrong result seen below...

enter image description here

A copy of my data is found here.

13

Convex hull - as mentioned by Kazuhito - is one option, but - depending on the cluster shape - you will get more appropriate polygons using concave hulls, for example implemented in ConcaveHull plugin.

enter image description here

7

You may be interested in Convex Hull which is in Processing | QGIS geoalgorithms | Vector geometry tools. There is Field option which can be used with Method Create convex hulls based on field.

enter image description here

Or from the menu Vector | Geoprocessing Tools | Convex Hull(s).

Many Thanks, Techie_Gus and underdark for information.

  • 1
    Note that in the latest QGIS release, i.e. 2.18, the Geoprocessing Tools menu is no longer under the Vector menu. It is now only accessible through the processing toolbox. – Techie_Gus Feb 26 '17 at 11:39
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    @Techie_Gus If you don't see a Geoprocessing Tools menu, that's a sign that you have an old Processing version in your plugin folder that should be deleted – underdark Feb 26 '17 at 17:45
  • Thanks @underdark. I will add drop-down list of 2.14/2.18 cases for clarity. – Kazuhito Feb 26 '17 at 18:17
  • @underdark I can see the processing tools menu as a separate menu but not under the vectors menu anymore. And by the way, I use the OSGEO4W installer. – Techie_Gus Feb 26 '17 at 18:20
  • What to do with polygons that overlap each other? – nagib Feb 27 '17 at 6:20

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