> <Doug_Newcomb <at> fws.gov> writes: > > Hi Folks,Here's the gdal command (gdal 1.6.2) I used to merge ~3500 1 meter NAIP > quarter quads (uncompressed geotiff TIFF) in 3 UTM projections into one Bigtiff Image > in the USGS Albers projection. It took about 15 hours ( on a 3 year old Intel Core2 > Duo 64 bit Centos 5.3 Linux box with 6GB RAM) and created an uncompressed, tiled, > bigtiff file of 485 GB. About 32 GB/hr. > gdalwarp -t_srs "+proj=aea +lat_1=29.5+lat_2=45.5 +lat_0=23.0 +lon_0=-96 > +x_0=0 +y_0=0 +ellps=GRS80 +datum=NAD83 +units=m no_defs <>" > -wo "SKIP_NOSOURCE" --config "GDAL_CACHEMAX=500" -wm=5000 > -co "TILED=YES" */*.tif /biggis/albers/nc_naip2008.tif > > In the above command, -t_srs "+proj=aea +lat_1=29.5 +lat_2=45.5 +lat_0=23.0 > +lon_0=-96 +x_0=0 +y_0=0 +ellps=GRS80 +datum=NAD83 +units=m no_defs <>" > indicates the target projection, -wo "SKIP_NOSOURCE" don't write > in areas for which there is no data for the current file, > --config "GDAL_CACHEMAX=500" set the cache memory at 500MB ( set this close > to the maximum input file size), -wm=5000 set the warp memory to 5000MB , > -co "TILED=YES" create a tiled tiff as output, */*.tif, use all of the tiffs > in all of the subdirectories as input files ( in this case there was one > directory for each of the 3 utm zones) , /biggis/albers/nc_naip2008.tif, > the output file name and location. >
Hi Doug, I finally tried your parameters and they did work fine for me also. I had something like hundred geotiffs, 400 MB each, and I was pushing them to bigtiff mosaic. I tried first with your *.tif selection and then again by using a virtual raster file as source, created from Mapserver tileindex shapefile with gdalbuildvrt. My Windows computer was handling about 20 GB/hour with cubic resampling (-rc) this time. Parameters -wo "SKIP_NOSOURCE" --config "GDAL_CACHEMAX=500" -wm=5000 seem to have a big influence on efficiency. I wonder if there are some rules of thumb for selecting values of GDAL_CACHEMAX and -wm. You said cachemax is good to be close to the maximum input file size, how about -wm? -Jukka Rahkonen- _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev
