Hi,

Have you considered to use https://gdal.org/programs/gdal_edit.html?

-Jukka Rahkonen-

-----Alkuperäinen viesti-----
Lähettäjä: gdal-dev <gdal-dev-boun...@lists.osgeo.org> Puolesta Andrea 
Giudiceandrea via gdal-dev
Lähetetty: maanantai 20. syyskuuta 2021 12.11
Vastaanottaja: gdal-dev@lists.osgeo.org
Aihe: [gdal-dev] TIF + TFW to GeoTIFF without decompression/recompression

Hi devs,
gdal_transalte has an "hidden" feature (not mentioned in the docs [1]), 
introduced since GDAL 1.10 [2], which allows to convert .JPG + .JPW raster 
layer to GeoTIFF without decompressing and recompressing the raster image (a so 
called "lossless conversion of JPEG into JPEG-in-TIFF" [3]).

It seem to me the same is not possible if the source is a .TIF (e.g. a
JPEG-in-TIFF) + .TFW raster layer. In this case the image is always 
decompressed and then recompressed if a compression method is specified, thus 
adding another unnecessary lossy step.

I think the decompression / recompression cycle should obviously not be needed 
converting a TIFF file to a GeoTIFF file (unless image manipulation options are 
specified) and gdal_transalte should just copy the source TIF file and add the 
proper GeoTIFF metadata tags taken from the TFW file and from the -a_srs 
parameter.

Maybe is there any other "hidden" feature I haven't been able to find yet?

Best regards.

Andrea Giudiceandrea


[1] https://github.com/OSGeo/gdal/issues/4510
[2]
https://github.com/OSGeo/gdal/commit/a77c726484d508f1ffff2b9f5a9a869313092687
[3]
https://erouault.blogspot.com/2014/04/advanced-jpeg-in-tiff-uses-in-gdal.html


Side notes:

I know gdal_edit could also be used, but it cannot automatically take the 
georeferencing parameters from the TFW file.

It could also be possible to use the geotifcp cli tool from libgeotiff, but it 
seems it (the one shipped by OSGeo4W) has some issues handling JPEG-in-TIFF 
files (while it works well with other compression formats): 
the "Warning, fractional scanline discarded." and "JPEGLib: Application 
transferred too few scanlines." errors are reported unsuccessfully trying to 
convert a JPEG-in-TIFF + TFW to a GeoTIFF.

Instead, the very old and almost nowhere to be found GeoTiffExamin gui tool can 
just add the proper GeoTIFF metadata tags, taken from the TFW file, to a TIFF 
file without modifying the raster image. Anyway the gui tool cannot be used for 
batch conversion.
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