.
With the Zonal statistics plugin, you can analyze
the results of a thematic classification. It allows you to calculate several values
of the pixels of a raster layer with the help of a polygonal vector layer (see
figure_zonal_statistics). You can calculate the sum, the mean value and the
total count of the pixels that are within a polygon. The plugin generates output
columns in the vector layer with a user-defined prefix.
Figure Zonal Statistics