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I'm looking for any GIS tool to do detailed rasterising of polygons. I've checked GDAL's gdal_rasterize command (and API), and ArcGIS's Polygon to Raster tool, but they only rasterise 1 attribute per cell, not an area-weighted aggregated attribute. Let me describe with an example. Consider that I need to rasterise values from polygons into a 100 m resolution raster. Here are three polygons contained in one pixel:

polygons in one pixel

Where the areas for each class are 4000, 2500, and 3500 m², or a weighting of 0.4, 0.25 and 0.35. If the values of the attribute that I need to rasterise are 12, 42 and 8, then their weighted values are 4.8, 10.5 and 2.8. The sum of the weights, 18.1, is the value that I would like to rasterise, since it is representative for the whole pixel. Most other rasterisation routines I'm aware of will choose 12, since that is the value of one of the polygons that is either at the centre of the cell or has the maximum area. 12 is not acceptable for my analysis, since it will skew the mass-balance for the whole raster, which is unacceptable.

I'm looking to see if there are better tools for rasterising. My current approach is to perform a vector analysis at the pixel level, using the intersection of polygons and each pixel, then combine the results into a raster. This is a slow process, as I have 80275 rows (each pixel).

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I'm pretty sure this question has appeared earlier in another guise, Mike: the solution is to rasterize with a finer cellsize, then aggregate to the desired cellsize using block statistics. Some of these terms might be useful keywords for a search. –  whuber Aug 8 '12 at 22:05

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