Hi Patrick,
It feels a bit strange that write support for CADRG is needed in 2025,
but besides that, your proposal sounds solid as far as I remember the
details of those formats. I guess the most interesting part will be
write support for vector quantization to figure out the VQ LUT that
minimize loss. Hopefully there is literature on the subject.
Even
Le 11/06/2025 à 14:51, Patrik Sylve via gdal-dev a écrit :
Hi,
We are exploring the possibility of adding write support for CADRG
format in GDAL and would appreciate some community feedback before
starting implementation.
There is currently no open-source workflow for creating CADRG. GDAL
can already read CADRG via RPFTOC/NITF drivers, so extending that work
feels like a good next step.
Short background on CADRG format:
CADRG is a Raster Product Format (RPF) that consists of a TOC file
referencing data frames. Each data frame is stored as a National
Imagery Transmission Format (NITF) message.
GDAL currently supports:
* Reading CADRG (a.toc) via the RPFTOC driver
* Reading individual CADRG frames via the NITF driver
* Writing NITF images, both without and with JPEG compression
To implement a CADRG writer, we could extend the existing NITF and
RPFTOC drivers:
NITF:
* Implement Vector Quantisation compression
* Add option to set Frame size
** A CADRG frame must be 1536x1536 pixels, so output would be tiled
* Add option to set CADRG scale
RPFTOC:
* Extend with 'write' mode
** Internally call NITF driver to generate CADRG compliant data frames
** Generate a .toc file per MIL-STD-2411
Example usage, create a CADRG from a TIF-file:
gdal_translate input.tif ./RPF \
-of RPFTOC \
-co "PRODUCT=CADRG" \
* # NITF file header options*
-co "FTITLE=My CADRG Product" \
-co "FSCLAS=U" \
...
Output:
└── RPF/
├─── a.toc
└─── frames/
├──── 00AVL01C.TL6
└──── 00AVM01C.TL6
Drivers:
* https://gdal.org/en/stable/drivers/raster/rpftoc.html
* https://gdal.org/en/stable/drivers/raster/nitf.html
Standards:
* CADRG:
http://everyspec.com/MIL-PRF/MIL-PRF-080000-99999/MIL-PRF-89038_25371/
* RPF: http://everyspec.com/MIL-STD/MIL-STD-2000-2999/MIL-STD-2411_6903/
Would this be a welcomed addition? Any thoughts or feedback is
appreciated.
Best regards / Vänliga hälsningar
*Patrik Sylve*
Software Developer
*
*
*E:***patrik.sy...@t-kartor.com
www.t-kartor.com <http://www.t-kartor.com/>
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