Hi I have been desperately trying to figure out how to solve the task described below in GRASS (via R using spgrass6). I have searched the list, but did not find exactly what I was looking for.
I have a large polygon file, app. 250000 polygons. It is the GLWD-2 data set available here <http://worldwildlife.org/publications/global-lakes-and-wetlands-database-small-lake-polygons-level-2> The map is in lat long. My goal is to end up with a raster layer in Behrmann projection with app 96486.28m by 96486.28m grid cells showing the area per grid cell covered by polygons in the GLWD-2 layer. So as I see it the task is to, for each grid cell, "clip" the underlying polygon file, calculate the area and return that value in the resulting raster. So far I have successfully imported the shape file and reprojected it to a location with the desired projection and resolution. So far so good. Then I imported a raster with the desired grid cell size and dimensions. So now I seem to have the layers I need in the same location. Then I some how want to do the actual clipping and calculation of the area of polygons in each cell. This is where I get stuck. Any suggestions to a newbie? Initially I thought I somehow could specify which function(e.g. sum, mean etc) should be used in v.to.rast in the case of multiple polygons falling in the same grid cell. But I could not find anything here. I'm running GRASS 7.0 on OSX btw. Any help and suggestions would be highly appreciated! Best regards, Lars -- View this message in context: http://osgeo-org.1560.n6.nabble.com/Rasterize-polygons-multiple-polygons-per-grid-cell-tp5005264.html Sent from the Grass - Users mailing list archive at Nabble.com. _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
