[Proj] Creating a nadgrid shift file
j.l.h.hartmann at uva.nl
Thu Jan 17 12:10:40 EST 2013
(Sorry for crossposting, don't know if it is a gdal or proj problem )
This has been discussed on this list some time ago. I have been able to
create a working nadgrid file with gdal, but it doesn't return the right
coordinates. I did it as follows:
- create a 4 band, float32 geotif, each pixel with the displacements in
lat, lon (arcseconds), errorx and errory (both zero)
- gdal-translate it to ntv2-format.
The displacements in the geotiff are correct, and proj returns shifted
coordinates when using the ntv2-file, but not on the right location. I'm
really out of my wits. Could it have something to do with ntv2 using
negative lon-values east of Greenwich? Any help would be appreciated.
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