On Wed, Mar 22, 2017 at 9:28 PM, Markus Metz <[email protected]> wrote: > On Wed, Mar 22, 2017 at 8:12 PM, Markus Neteler <[email protected]> wrote: ... >> Nikos, for an even bigger map try >> >> Global Surface Water (2000-2012, 30 m, Data coverage is from 80° north >> to 60° south): >> http://landcover.usgs.gov/glc/WaterDescriptionAndDownloads.php >> by USGS. 1.6GB in size. >> >> Using gdalbuildvrt I created a VRT from the 504 GeoTIFF files. >> >> After import into GRASS GIS, here the timings: >> >> # final map size: >> g.region -p >> ... >> rows: 493200 >> cols: 1296001 >> cells: 639187693200 >> >> (handling only works in GRASS GIS 7.3.svn since Markus Metz's recent >> improvements on global data import are needed). > > (my changes were bug fixes, not improvements) > >> >> Benchmarks: >> - Import took 2h while reading the data from a CIFS mounted storage >> box (slow) and writing on SSD. >> - Displaying the entire map (639 giga-pixel) in GRASS GIS' display >> (d.mon) took ~15 sec over a ssh tunnel from my laptop to the server, >> since I am at a conference. >> >> Fair deal I would say :-) > > A bit more information would help to compare: > - what is your GDAL version?
GDAL 2.1.2 > - are 504 GeoTIFF files compressed? If yes, which method? Yes, COMPRESSION=LZW > - what are the block dimensions of the input GeoTIFFs? Size is 36001, 36001 - Block=36001x1 Type=Byte > - what kind of GRASS compression did you use? Default raster + NULL compression enabled. I.e., r.compress -p watermask2010 <watermask2010> is compressed (method 2: ZLIB). Data type: CELL <watermask2010> has a compressed NULL file Again, the fact that I had to read from an attached storage box likely slowed down the import. Just thought to post these numbers here. markusN _______________________________________________ gdal-dev mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/gdal-dev
