[gdal-dev] gdal_rasterize processed GTiff filesize question

[Rahkonen Jukka]

Hi,

I suppose that something similar than with gdalwarp https://trac.osgeo.org/gdal/wiki/UserDocs/GdalWarp#GeoTIFFoutput-coCOMPRESSisbroken happens but with gdal_rasterize I think there are no tricks that could help.

-Jukka Rahkonen-

Lähettäjä: Andrey VI <andrey_vi at list.ru>
Lähetetty: tiistai 19. maaliskuuta 2024 18.09
Vastaanottaja: Rahkonen Jukka <jukka.rahkonen at maanmittauslaitos.fi>
Kopio: gdal-dev at lists.osgeo.org
Aihe: Re: [gdal-dev] gdal_rasterize processed GTiff filesize question

Yes, the target files already exists. Yes, I’ve tried to investigate this issue on some small and medium files. For example:
original hillshade.tif size is 11469 bytes, after gdal_rasterize its size is 26465 bytes, and after gdal_translate - 15426 bytes,
original - 7477 K, gdal_rasterize - 8705 K, gdal_translate - 5964 K,
original - 39110 K, gdal_rasterize - 39112 K, gdal_translate - 446 K.
So, it depends on the content of the raster.
I would like to avoid intermediate processing if possible. This will require additional time for processing and space for the data. Moreover, in some cases a lot of space needs to be allocated for intermediate files.

Andrey
Tuesday, March 19, 2024 4:25 PM +03:00 from Rahkonen Jukka <jukka.rahkonen at maanmittauslaitos.fi</compose?To=jukka.rahkonen at maanmittauslaitos.fi>>:


Hi,



So the target files dem.tif and hillshade.tif exist already? Maybe it is not so simple to update already compressed data in place. Have you tried what happens if you re-write the results into new files

gdal_translate -co tiled=yes -co compress=LZW hillshade.tif final_hillshade.tif.



-Jukka Rahkonen-



Lähettäjä: gdal-dev <gdal-dev-bounces at lists.osgeo.org<mailto:gdal-dev-bounces at lists.osgeo.org>> Puolesta Andrey VI via gdal-dev
Lähetetty: tiistai 19. maaliskuuta 2024 14.43
Vastaanottaja: gdal-dev at lists.osgeo.org<mailto:gdal-dev at lists.osgeo.org>
Aihe: [gdal-dev] gdal_rasterize processed GTiff filesize question



Hello.



I’m using gdal_rasterize to remove some data from DEM (Int16) and hillshade (Byte) rasters with shape-file, like this:

gdal_rasterize -burn -32768 shape.shp dem.tif and gdal_rasterize -burn 0 shape.shp hillshade.tif

Both DEM and hillshade GTiffs created with -co COMPRESS=LZW -co TILED=YES options. After processing with gdal_rasterize the size of GTiffs becomes 1.5 times larger. Why it happens? I assumed that it should be the other way around, because a significant portion of the data is replaced with the same values and should be compressed well.



Andrey
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