Opened 18 years ago
Last modified 17 years ago
#1184 closed defect (fixed)
Reprojection doesn't deal with +nadgrids
Reported by: | Owned by: | warmerdam | |
---|---|---|---|
Priority: | high | Milestone: | |
Component: | OGR_SRS | Version: | unspecified |
Severity: | normal | Keywords: | |
Cc: | Markus Neteler |
Description
Ogr2ogr (the same for gdal_warp, I believe) doesn't handle +nadgrids="..." switch for datum shifts, e.g in: ogr2ogr -f "GML" \ -s_srs "+proj=tmerc +lat_0=0 +lon_0=9 +k=1.000000 +x_0=3500000 +y_0=0 +ellps=bessel +nadgrids=DHDN_ETRS89.gsb +units=m" \ -t_srs "+proj=utm +datum=WGS84 +zone=32" trf.xml org.xml the grid is ignored.
Change History (5)
comment:2 by , 17 years ago
Uwe, I've made an addition to the OGRSpatialReference that show allow preserving exact PROJ.4 syntax in the intermediate wkt representation as an extension node. Could you try something like: ogr2ogr -f "GML" \ -s_srs "+proj=tmerc +lat_0=0 +lon_0=9 +k=1.000000 +x_0=3500000 +y_0=0 +ellps=bessel +nadgrids=DHDN_ETRS89.gsb +units=m +wktext" \ -t_srs "+proj=utm +datum=WGS84 +zone=32" trf.xml org.xml Note the addition of +wktext to the proj.4 definition with the nadgrids definition. The code changes should have been in GDAL 1.4.0, or you could test with a recent FWTools release.
comment:4 by , 17 years ago
(In reply to comment #2) Frank, > Could you try something like: > > ogr2ogr -f "GML" \ > -s_srs "+proj=tmerc +lat_0=0 +lon_0=9 +k=1.000000 +x_0=3500000 +y_0=0 > +ellps=bessel +nadgrids=DHDN_ETRS89.gsb +units=m +wktext" \ > -t_srs "+proj=utm +datum=WGS84 +zone=32" trf.xml org.xml > > Note the addition of +wktext to the proj.4 definition with the nadgrids > definition. > Works with FWTools1.2.0!! I had problems specifying the grid file under windows. The program always looked it up under <FWToolsInstallDir>/proj_lib. I haven't found a way to specify an other place. Even absolute paths are appended to the above mentioned installation path. Setting PROJ_DEBUG was a great help for finding this out. Thank you very much, Frank!!
comment:5 by , 17 years ago
Uwe, Could you file a bug against PROJ.4 about the absolute paths not working, with some detailed examples of forms that did not work. The pj_open_lib() function attempts to recognise absolute paths, but I see it does not recognise drive name prefixes, and on windows it will only recognise \ as a path sep. not /. I'll try and improve this before the next PROJ.4 release. At some point I may consider adding special cases of the PROJ.4 to WKT translation where the need to preserve the original PROJ.4 string is recognised. But I hesitate to go there quite yet.
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