On Wed, Mar 09, 2011 at 06:05:20PM -0600, Marius Jigmond wrote: > On Wed, 2011-03-09 at 12:35 -0500, Frank Warmerdam wrote: > > On 11-03-09 11:51 AM, Wendell Turner wrote: > > > > > > Do any of the gdal utilities crop an image on non-square > > > boundaries? > > > ... > > I think gdalwarp with -crop_to_cutline and a cutline specified > > with the shape will accomplish what you want. > > http://www.gdal.org/gdalwarp.html > > The cutline comes from an OGR supported file but this can be as simple > > as a .csv file with a WKT geometry in it. The -crop_to_cutline may be > > new to 1.8. > > Wendell, > > Please be aware that this method may introduce raster shifting and > possibly resampling (depending on the original cell size). It might or > might not matter for your purposes. A better approach is to use > gdal_translate with -projwin to extract to shape envelope and then > gdal_rasterize with -i to burn nodata where shape is missing.
Marius & Frank, The -crop_to_cutline worked as advertised, and I didn't notice any shifting or resampling. However, it seemed to place the cropped image into a larger bounding box and the pixels that are outside the cropping shapefile are black, not transparent. The gdal_rasterize with -i looks interesting, but my input is raster, not vector, and gdal_rasterize doesn't seem to like that. Is there a way to force pixels outside of the cropping polygon to be 'not there', or transparent? Is there a burn value that indicates that? Wendell _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
