[Qgis-user] Raster data aggregation in Polygons

[Paulo van Breugel]

In GRASS you could do:

   - Convert vector file to raster (*v.to.rast.attr*), using the land use
   class as raster category
   - Use* r.stats* or* r.report *to calculate coverage of each land use
   class. The r.report functions offer more output options, the r.stats output
   is easier to use in e.g., a spreadsheet.

These GRASS GIS commands are also available in the GRASS toolbox or the
Sexante Toolbox in QGIS. To find the functions mentioned above, both
toolboxes have a filter / search box making it easy to find any command /
function.

Note that to the GRASS toolbox you will need the extra step of importing
your data in a GRASS GIS database. If you don't have your data in a GRASS
GIS database, you probably want to try the Sextante toolbox.






On Sun, Dec 2, 2012 at 11:43 AM, Dietrich Heintz <dheintz at gmx.net> wrote:

> Hi all,
> I have a raster with landuse classification from Modis and would like
> to aggregate the hectarage of each class within administrative boundaries.
>
> Is there a tool in QGIS or Grass that aggregates the percentual coverage
> of each (landuse) class within each feature of the shape directly from
> the raster?
>
> At the moment I polygonize and intersect, but it turned out to be very
> time consuming,
> due to the processing.
>
> If someone has a useful idea or solution I would be very much pleased.
>
> Dieter
>
>
> _______________________________________________
> Qgis-user mailing list
> Qgis-user at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/qgis-user
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/qgis-user/attachments/20121202/17542354/attachment.html>