Reading the whole VRT is slower than reading the equivalent single raster map. Only reading small parts of the VRT provides a performance benefit.
A GRASS virtual raster can be regarded as a simplified version of GDAL's virtual raster format. The GRASS equivalent is simpler because issues like nodata, projection, resolution, resampling, masking are already handled by native GRASS raster routines.
# set the region g.region raster=elev_state_500m -p # higher resolution g.region res=50 -p # resample the DEM to 50 meter r.resamp.interp input=elev_state_500m output=elev_state_50m method=bilinear # create tiles r.tile input=elev_state_50m output=elev_state_50m_tile_ width=1000 height=1000 overlap=0 # dump list of tiles to a file g.list type=raster pattern=elev_state_50m_tile_* output=tilelist # build a vrt r.buildvrt file=tilelist output=elev_state_50m_vrt
The equivalent GDAL utility gdalbuildvrt
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