[Gdal-dev] Bypassing PROJ.4

Richard didier didier.richard at ign.fr
Wed Sep 1 10:34:20 EDT 2004

Hi all,

I would like to use the GDAL utilities (mainly gdalwarp) but wouldn't like to 
use PROJ.4 library.

The issue is that we have algorithms for coordinates transformations. We have 
compared results from PROJ.4 and our library and we lost the initial 
coordinates resolution with PROJ.4. Further more, we use specific datum shift 
grids that are not compatible with the one (NAD83) plugged into PROJ.4.

I feel like several solutions can be used, but I'd like to have experts 
opinion. As far I can see, I feel like making a PROJ.4 wrapper to call our 
coordinates transformation library. Still, I have to pass our SRS ID to GDAL 
utilities (I then need to write some ogr_srs_ignrig.cpp files to do it).

Finally, we like to add a -rsi resampling option (sinus cardinal resampling, 
very slow, but really efficient for image geometry quality) to gdalwarp, but 
I don't know exactly where to add it in the source tree.

Thanks in advance for your advices,

Didier RICHARD, chef de projet "Diffusion des données numériques" 
Institut Geographique National           tel: +33/0
2/4 Avenue Pasteur                       fax: +33/0
F-94165 St-Mande Cedex                e-mail: Didier.Richard at ign.fr

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