[Proj] NTV2 Grid Shift files and gdalwarp
j.l.h.hartmann at uva.nl
Tue Jun 25 04:12:41 EST 2013
I've been experimenting with grid-shift files in ntv2 format to
rubbersheet old maps. I created a working ntv2-file as described in
and added an epsg definition for PROJ and PostGIS. The thing works with
cs2cs and with vector transforms in PostGIS, but when I try to warp a
raster file I get lots of errors like:
Inverse grid shift iterator failed to converge.
pj_apply_gridshift(): failed to find a grid shift table for
and an output file with rubbish
The location is within the grid.
The source raster has epsg:28992, without the +towgs84 parameters but
with the ntv2 file, the output raster has epsg:28992 with the towgs84
numbers. Essentially, the ntv2 file contains the distances between the
scanned map locations translated to an approximate position in
epsg:28992, and the correct ones. I computed the grid with boundaries
far outside the mapped regions, but this does not seem to make a difference.
Can anyone help?
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the Proj