Re: [gdal-dev] Just want to do simple batch compression...
srygonic wrote > The issue is that the image turns out to be completely black for me... not > too sure what I'm doing wrong here. > > I understand that it might be better to cut up the files but that would > take > too long (as there are too many files) and I'm wondering if there is a > faster solution here to reduce the size before taking that route. > > Will look into this gdalbuildrvt as well once I'm back at the computer > tomorrow... any good tutorials for me to start off with? > > Thanks for the assistance and the help Jukka! Hi, I had another look at the GAPS_2017-02-23.tif file and I would recommend that do not waste your time for improving it as one image. It is a 3-band image of sixe 128478 by 133220 pixels and thus as uncompressed it would make about 50 gigabytes. The current file size 450 GB is not bad especially because the image includes a good set of overviews. Image also opens and works fine with QGIS. I have no ready made recipe for automatic selection and extracting of areas which contain data. I guess that I would have a try by vectorizing the raster files with http://www.gdal.org/gdal_polygonize.html first and build windows for gdal_translate and -projwin based on the vector data. It could be interesting as an exercise but probably there should be hundreds of images before it really saves enough resources for being a good investment. -Jukka Rahkonen- -- Sent from: http://osgeo-org.1560.x6.nabble.com/GDAL-Dev-f3742093.html ___ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
Re: [gdal-dev] Just want to do simple batch compression...
The issue is that the image turns out to be completely black for me... not too sure what I'm doing wrong here. I understand that it might be better to cut up the files but that would take too long (as there are too many files) and I'm wondering if there is a faster solution here to reduce the size before taking that route. Will look into this gdalbuildrvt as well once I'm back at the computer tomorrow... any good tutorials for me to start off with? Thanks for the assistance and the help Jukka! -- Sent from: http://osgeo-org.1560.x6.nabble.com/GDAL-Dev-f3742093.html ___ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
Re: [gdal-dev] Just want to do simple batch compression...
srygonic wrote > I have a lot of geotiffs which are quite large at times (meaning they have > quite a bit of unnecessary white space between) and I would like to run a > batch script to just do a simple compression on them as I believe that > they > are not compressed because the files that just contain a lot of white > space > are still unnecessarily huge. Hi, If you run gdalinfo about your image you will notice that it is already compressed: Metadata: TIFFTAG_SOFTWARE=OrbitGIS 17.0.0 Image Structure Metadata: COMPRESSION=YCbCr JPEG INTERLEAVE=PIXEL SOURCE_COLOR_SPACE=YCbCr However, one of your commands which is using actually the same parameters does shrink the image from 465 MB into 170 MB. gdal_translate GTIFF_RAW:GAPS_2017-02-23.tif test2.tif -co PHOTOMETRIC=YCBCR -co TFW=YES -co TILED=YES -co BIGTIFF=IF_SAFER -co COMPRESS=JPEG -a_srs EPSG:3414 For saving disk space I would consider cutting those areas which do have real data into individual files and then combine them into a virtual mosaic with gdalbuildvrt. Empty space does compress rather well but not having any pixels from areas with no data is most savvy option of all. -Jukka Rahkonen- -- Sent from: http://osgeo-org.1560.x6.nabble.com/GDAL-Dev-f3742093.html ___ gdal-dev mailing list gdal-dev@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/gdal-dev
