[Qgis-user] Aggregation of polygons into vector grid
Micha Silver
micha at arava.co.il
Tue Oct 4 22:10:10 PDT 2011
On Tue, 2011-10-04 at 16:55 +0200, Sebastian Schubert wrote:
> Hi,
>
> I have a map with several polygons i, each having a certain value x_i. I
> want to calculate the average value of x in a rectangular grid. Each
> cell j of this grid includes (parts of) several polygons with A_ij being
> the area of the part of polygon i being in grid cell j. With that the
> average value in grid cell j is
>
> x_j = sum_i A_ij x_i / (sum_i A_ij)
>
> I was able to create a grid with Vector > Research Tools > Vector grid.
> Now each cell of this grid should include the average value of all
> polygons inside the cell (as described above).
>
> Any idea how to do that?
>
You probably want to look at the GRASS module v.rast.stats
> Thanks a lot!
> Sebastian
>
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