I'm trying to generate the fractional coverage of land-cover within polygon grid cells. My land-cover is a 30m raster dataset (10008x8939 cells) and my grid is a fishnet shapefile (approximately 1km resolution; 120x111 cells).
What I normally do is create a fishnet corresponding to the raster, then sample the raster using the fishnet labels, and join the labels back to the grid polygon. This way I convert the raster into a polygon. Using the arctoolbox Raster to Polygon tool does not work so well for me because it does not give me a raster cell by cell representation of the data; even with "simplify polygons" unchecked.
With the raster as a polygon I can intersect it with the fishnet and do some calculations to get the fraction of land-cover types within each fishnet cell.
This worked really well until I got to this 30m dataset. Already ArcMap complains about a 2gb limit when trying to create the grid the raster will lay on.
Is there any other ideas?
A polygon grid that large will take ages to process.
The other answers related to this question seem to consider some sort of resampling and not relating the data to an arbitrary non-aligned grid.