John -
Are the input and output files on the same disk subsystem, and what kind of disk(s) is involved? gdalwarp will run as a single task, so if it uses 1 processor 100% of the time you'll see 25% utilization. If you run two gdalwarp jobs at the same time, using the same disks, you can very easily cause disk thrashing and bog the whole process down, so it's not surprising to find two jobs in parallel takes more than two jobs run serially. If possible, have the input and output files on different disks, and avoid having read/write activity on the same disk or more than one job writing to the same disk. - Ed Ed McNierney President and Chief Mapmaker TopoZone.com / Maps a la carte, Inc. 73 Princeton Street, Suite 305 North Chelmsford, MA 01863 Phone: 978-251-4242, Fax: 978-251-1396 [EMAIL PROTECTED] From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of John Mitchell Sent: Monday, May 14, 2007 5:52 PM To: [EMAIL PROTECTED]; Gdal-Dev; [email protected] Cc: Mark A Hollis Subject: [Gdal-dev] speeding up the gdalwarp process for mosaicing andreprojection Hi, I have run the following gdalwarp command gdalwarp.exe -wo SKIP_NOSOURCE=YES -rc -s_srs EPSG:" + EPSG + " -t_srs EPSG:" + EPSG_wgs84 + " -of HFA " + " -q " + inputFiles + " " + outputFile against a group of geotiff files which both mosaics and reprojects them to wgs84 and it works fine, but it takes 22:47 hours to generate the 52.89 GB mosaic. Does anyone have any suggestions on how to speed up the gdalwarp process. I have noticed that the 4 processor server is only being utilized between 14-26% across all 4 processors. Is their a way to force a higher utilization of these processors? I have in past tried to run 2 gdalwarp jobs simultaneously and I have noticed that it takes them much longer compared to the total time when running serially (meaning one after the other). Thanks, -- John J. Mitchell
