[FWTools] An issue about using GDALWARP to do the NTv2 transformation

Mon Dec 13 03:04:44 EST 2010

Hi there,

Last week I sent an query (forwarded as below) to the FWTools mailing list. As the attachment is too big, the posting is still awaiting the moderator's approval. I am now re-sending another email for the same query without the attachment (showing the messages displayed in the FWTools Shell window after running the GDALWARP command). As follows, please find the GDAL command and some of the messages copied from the window:

C:\Program Files\FWTools2.4.7>gdalwarp -s_srs "+proj=tmerc +lat_0=0 +lon_0=12 +k
=1.000000 +x_0=4500000 +y_0=0 +ellps=bessel +datum=potsdam +nadgrids=C:\fh\comar
ch\BETA2007.gsb +units=m +wktext" -t_srs "+proj=utm +datum=WGS84 +zone=32" C:\fh
\comarch\backdrops\s4_01_01\l0.tif C:\fh\comarch\backdrops\s4_01_01\l0_test.tif
pj_open_lib(proj_def.dat): call fopen(C:\PROGRA~1\FWTOOL~1.7\proj_lib\proj_def.d
at) - succeeded
pj_open_lib(proj_def.dat): call fopen(C:\PROGRA~1\FWTOOL~1.7\proj_lib\proj_def.d
at) - succeeded
Processing input file C:\fh\comarch\backdrops\s4_01_01\l0.tif.
pj_open_lib(proj_def.dat): call fopen(C:\PROGRA~1\FWTOOL~1.7\proj_lib\proj_def.d
at) - succeeded
pj_open_lib(proj_def.dat): call fopen(C:\PROGRA~1\FWTOOL~1.7\proj_lib\proj_def.d
at) - succeeded
pj_open_lib(C:\fh\comarch\BETA2007.gsb): call fopen(C:\fh\comarch\BETA2007.gsb)
- succeeded
NTv2 DHDN90   62x84: LL=(5.5,47) UR=(15.6666667,55.3)
pj_apply_gridshift(): failed to find a grid shift table for
                      location (5.0347670dW,55.2216906dN)
   tried: C:\fh\comarch\BETA2007.gsb
0pj_apply_gridshift(): failed to find a grid shift table for
                      location (5.0350256dW,55.2215588dN)
   tried: C:\fh\comarch\BETA2007.gsb
pj_apply_gridshift(): failed to find a grid shift table for
                      location (5.0350256dW,55.2215588dN)
   tried: C:\fh\comarch\BETA2007.gsb
NTv2 - loading grid DHDN90
pj_open_lib(C:\fh\comarch\BETA2007.gsb): call fopen(C:\fh\comarch\BETA2007.gsb)
- succeeded
pj_apply_gridshift(): used DHDN90
pj_apply_gridshift(): used DHDN90
pj_apply_gridshift(): used DHDN90
pj_apply_gridshift(): failed to find a grid shift table for
                      location (5.0350534dW,55.2212791dN)
   tried: C:\fh\comarch\BETA2007.gsb
pj_apply_gridshift(): failed to find a grid shift table for
                      location (5.0350534dW,55.2212791dN)
   tried: C:\fh\comarch\BETA2007.gsb
pj_apply_gridshift(): used DHDN90
pj_apply_gridshift(): used DHDN90
pj_apply_gridshift(): used DHDN90
pj_apply_gridshift(): failed to find a grid shift table for
                      location (5.0350813dW,55.2209994dN)
   tried: C:\fh\comarch\BETA2007.gsb
pj_apply_gridshift(): failed to find a grid shift table for
                      location (5.0350813dW,55.2209994dN)
   tried: C:\fh\comarch\BETA2007.gsb
pj_apply_gridshift(): used DHDN90
pj_apply_gridshift(): used DHDN90
pj_apply_gridshift(): used DHDN90
pj_apply_gridshift(): failed to find a grid shift table for
                      location (5.0351091dW,55.2207198dN)
   tried: C:\fh\comarch\BETA2007.gsb
.................................
.................................
.................................
pj_apply_gridshift(): failed to find a grid shift table for
                      location (5.1075622dW,54.4761871dN)
   tried: C:\fh\comarch\BETA2007.gsb
pj_apply_gridshift(): failed to find a grid shift table for
                      location (5.1075622dW,54.4761871dN)
   tried: C:\fh\comarch\BETA2007.gsb
pj_apply_gridshift(): failed to find a grid shift table for
                      location (5.1075888dW,54.4759073dN)
   tried: C:\fh\comarch\BETA2007.gsb
pj_apply_gridshift(): failed to find a grid shift table for
                      location (5.1075888dW,54.4759073dN)
   tried: C:\fh\comarch\BETA2007.gsb
100 - done.

I did not copy all the error messages here as there are quite an amount of messages. Although we did get some resulting file after running this command, I did not manage to see anything (blank) when displaying the file in any map data/image tool. As I mentioned in the last email, the NTv2 transformation seemed to be working perfectly on all my MapInfo vector data by running the ogr2ogr command while it all failed when running the GDALWARP command to do the NTv2 transformation on the raster data by using the same grid shift file and the same source/target projection settings. 

I am just wondering whether you are aware of any reason why this happens. More information regarding this issue could be found in the below forwarded email.

Anyway, your help would be much appreciated.

Thanks & Best Regards,
Heng

From: Heng Feng 
Sent: 07 December 2010 09:11
To: 'FWTools at lists.maptools.org'
Subject: A question about using GDALWARP to do the NTv2 transformation
Importance: High

Hi there,

I was trying to use GDALWARP command to do the NTv2 transformation on some German map data. However I have come across a lot of errors saying "failed to find a grid table for the location". I have used the same grid shift file and the ogr2ogr command with the same projection settings on the MapInfo map data files for the NTv2 transformation. It seems working perfectly without any error message. The grid shift file was downloaded from this link: http://translate.google.com/translate?js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&sl=de&tl=en&u=http%3A%2F%2Fcrs.bkg.bund.de%2Fcrseu%2Fcrs%2Fdescrtrans%2FBeTA%2Fde_dhdn2etrs_beta.php.

I am just wondering whether those errors are caused by the map data themselves. It seems that I got the error messages for all the raster map data I have got here by running the GDALWARP command to do the NTv2 transformation on them. I have attached two screenshots for your reference. Should you need any further information regarding this issue, please let me know.

Thanks & Regards,
Heng Feng

AIRCOM International
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