Analyzing weather stations coverage using a Voronoi diagram
Voronoi diagrams are a very useful tool to build influence regions from a set of points and the Spatial Extension provides a convenient function to build them. An example application of these diagrams is the calculation of the coverage areas of a series of weather stations. In the following query we are going to calculate these influence areas in the state of New York.
The result can be seen in the visualization below, where the color of each polygon indicates its area, which gives an insight on the coverage provided by the station.
Prior to the calculation of the Voronoi diagrams, the weather stations belonging to the New York State are collected from the table
ghcn_d.ghcnd_stations by filtering them against the state’s boundary. This same boundary is also used to clip the resulting Voronoi polygons: since a null bounding box parameter is passed to
ST_VORONOIPOLYGONS, the polygons otherwise would extend all over the map.
With this simple analysis we can identify at a glance areas where the coverage should be improved and therefore new stations are needed.