Frank and all, I would like to use the GRASSDataset class to access raster layers stored in GRASS database, but can't figure out how to do it. 1. Should I have libgrass installed? 2. What file should I supply to GDALOpen() -- the raster header (in <mapset>/cellhd directory), raster itself (<mapset>/cell or fcell), or something else? Thank you, Aleksey