On Mon, Sep 19, 2016 at 9:49 PM, Helmut Kudrnovsky <[email protected]> wrote: [...] > > --------- > original geotif with gdal_translate -co COMPRESS=LZW -co PREDICTOR=2 > > ls -l > total 279600 > -rw-r--r-- 1 88170601 Sep 19 19:07 CHELSA_bio01_1979-2013_V1_1_eur.tif > -rw-r--r-- 1 56511749 Sep 19 19:13 CHELSA_bio02_1979-2013_V1_1_eur.tif > -rw-r--r-- 1 69376203 Sep 19 19:16 CHELSA_bio03_1979-2013_V1_1_eur.tif > -rw-r--r-- 1 72247104 Sep 19 19:19 CHELSA_bio04_1979-2013_V1_1_eur.tif > > --------- > r.in.gdal and GRASS_COMPRESSOR=ZLIB > > ls -l > total 305909 > -rw-r--r-- 1 82287638 Sep 19 19:28 CHELSA_bio01_zlib > -rw-r--r-- 1 77139587 Sep 19 19:28 CHELSA_bio02_zlib > -rw-r--r-- 1 74791532 Sep 19 19:28 CHELSA_bio03_zlib > -rw-r--r-- 1 79030011 Sep 19 19:28 CHELSA_bio04_zlib > > --------- > r.in.gdal and GRASS_COMPRESSOR=BZIP2 and GRASS_INT_ZLIB=9
Note that GRASS_INT_ZLIB affects only ZLIB compression. > > ls -l > total 311983 > -rw-r--r-- 1 84163200 Sep 19 19:21 CHELSA_bio01 > -rw-r--r-- 1 78882189 Sep 19 19:22 CHELSA_bio02 > -rw-r--r-- 1 74892325 Sep 19 19:22 CHELSA_bio03 > -rw-r--r-- 1 81530621 Sep 19 19:22 CHELSA_bio04 > > ----------- > > at least in this case of data, r.external to '-co COMPRESS=LZW -co > PREDICTOR=2' geotiffs saves more disk space than import (regardless of the > GRASS_COMPRESSOR). If you want to save a lot of disk space, you can convert FCELL maps to CELL maps, e.g. for temperature values rounding to Celsius * 10, then check again which compressor best fits your needs. In previous tests I found that BZIP2 only gives me a disk space advantage for large maps with >10000 columns. Also, it seems that BZIP2 might compress integer maps better than fp maps. Markus M _______________________________________________ grass-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-dev
