New answers tagged

2

Two possibilities come to me: Categorized styling. Once you have applied the categorized style to your layer, you should see the different categories into the TOC. Each category is fitted with a tick box that you can tick or untick to display / hide points belonging to each category. Query via Select by expression. You can also select points via a query ...


1

Complementing @MikeT answer... For MS Windows: Requirements: Any Visual C++ Express version such as this The kmeans-postgresql module. What you will do: Tweak the source code to export the kmeans function to a DLL. Compile the source code with cl.exe compiler to generate a DLL with kmeans function. Put the generated DLL into PostgreSQL\lib folder. ...


4

This technique will work in versions of PostGIS < 2.2.0. Create cluster polygons by buffering the points by half your cluster distance, assign a cluster ID, then transfer the cluster ID to the points the polygons intersect: --Buffer all points by the half the cluster distance (in this case 40 metres), --merge into a multipolygon using st_union(), --then ...


5

If you can updgrade to postgis 2.2.0 you might be lucky because that feature has just been introduced. From the doc: "ST_ClusterWithin is an aggregate function that returns an array of GeometryCollections, where each GeometryCollection represents a set of geometries separated by no more than the specified distance." Check this: ...



Top 50 recent answers are included