Hi All, I have a large *.tif raster data set ( 92000 * 69000 cells of one meter, projection EPSG:25832 - ETRS89 / UTM zone 32N ) It contains integer values 1 to 20 and has a file size of about 100 MB in "Byte - Eight bit unsigned integer" format. Now the result is a rectangle and I wanted to cut it down to the area of interest (via cutline gdal option) using a shape polygon file (with one continuous polygon inside) to and set all values outside the area of interest of that rectangle to NULL values (for example setting 0 as NULL data values). I used the QGIS ( QGIS v 3.12 on windows) Menu RASTER > Extraction > Clip Raster by mask Layer which is based on gdalwarp.
That is when I am running into the problem that the 'cut' file size increases enormously and I ended up wit 50 times bigger file ( 5 GB size ! ) when I was actually expecting a smaller file size than before. I have not really an idea why the file becomes so enormously bloated. The same is the cass when I try gdalwarp directly on the command line or when using the QGIS Raster calculator or any other method I tried so far. How can I manage to get a smaller file size ( aka the 100 MB file size I started of with ) and which tools or formats are recommended to achieve this ? Cheers Karsten Karsten Vennemann <http://www.terragis.net> www.terragis.net
_______________________________________________ Qgis-user mailing list [email protected] List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
