Hi Uwe, Thanks for your reply. The l0.tif file does not contain any georeferenced information. However, I have run the GDALINFO command on another raster data file which is in the same map data set provided by the customer and hence is supposed to be georeferenced in the way as the l0.tif file. The command output is sent as attached. As mentioned before, I also did the NTv2 transformation on this raster data file (Notrufzonen_50m_v11_6_EPOS.tif) with the same GDALWARP command and the same grid shift file. I also got a lot of error messages saying that some coordinates are outside the area of the grid shift file. And with the "+x_0=500000" parameter, the output error messages are much less than the ones with the "+x_0=4500000" parameter.
Thanks for your help again. BR, Heng From: Schmitz, Uwe [via OSGeo.org] [mailto:ml-node+5852724-406096449-308...@n2.nabble.com] Sent: 20 December 2010 18:51 To: Heng Feng Subject: AW: [gdal-dev] An issue about using GDALWARP to do theNTv2transformation Heng, > > > http://osgeo-org.1803224.n2.nabble.com/file/n5848200/gdalwarp_<http://osgeo-org.1803224.n2.nabble.com/file/n5848200/gdalwarp_?by-user=t> > problem1.doc > gdalwarp_problem1.doc > Hi Uwe, > > I have tried your suggestion on the same raster file with a modified > "+x_0=500000" parameter in the command line (as seen in the > attached doc). I > could see the major difference:there is still one error > message left. When I > tried on another raster file with the same modified > parameter, I have got > much less error messages than before. However, is it still > possible that my > raster data are outside the area of the grid shift file? All > the raster data > I was trying to transform are GK (DHDN) zone 4, which false > easting value is > 4500000. This was why I used "+x_0=4500000" instead of > "+x_0=500000" in the > command line. As I am getting to know all these georeference > settings at the > moment, can you tell me why you suggested the modified > parameter and what > you meant about "raster data lacks the Gauss-Krueger meridian prefix"? > that was just a guess, because your coordinates lie far in the west of DHDN/GK zone 4. Normally DHDN/GK coordinates are noted as e.g.: 4500000.0 Rechts 5500000.0 Hoch Omitting the Gauss-Krueger meridian prefix you have: 500000.0 Rechts 5500000.0 Hoch (Note: Rechts coordinate has only six digits) an thats far in the west of the real position. It's very simple and therefore you may give it a try. If it's not the case, may be you can post the output of: gdalinfo l0.tif That would help to see, if the file is correctly georeferenced. Regards Uwe _______________________________________________ gdal-dev mailing list [hidden email]</user/SendEmail.jtp?type=node&node=5852724&i=0> http://lists.osgeo.org/mailman/listinfo/gdal-dev ________________________________ View message @ http://osgeo-org.1803224.n2.nabble.com/An-issue-about-using-GDALWARP-to-do-the-NTv2-transformation-tp5838904p5852724.html To unsubscribe from An issue about using GDALWARP to do the NTv2 transformation, click here<http://osgeo-org.1803224.n2.nabble.com/template/NamlServlet.jtp?macro=unsubscribe_by_code&node=5838904&code=aGVuZy5mZW5nQGFpcmNvbWludGVybmF0aW9uYWwuY29tfDU4Mzg5MDR8MTI3MzEwMjEw>. AIRCOM International http://www.facebook.com/Aircom | http://www.twitter.com/aircomint | http://blog.aircominternational.com/ | http://www.youtube.com/aircomint Disclaimer: This e-mail message is confidential and should not be used by, or disclosed to, anyone except the addressee. If you receive this message in error, please advise us immediately on +44 (0) 1932 442000. Since e-mail transmission is not secure or error free, we do not accept responsibility for changes to any e-mail which occur after it has been sent. Attachments to this e-mail may contain software viruses which could damage your systems. You should therefore virus-check all attachments before opening. AIRCOM may monitor incoming and outgoing emails through its networks and by responding to this email, you consent to such monitoring. The views and opinions expressed in this e-mail are those of the author only and not of AIRCOM. We do not intend to enter into any legal commitments or contracts by e-mail. Registered Office: Cassini Court, Randalls Research Park, Randalls Way, Leatherhead, Surrey, KT22 7TW, UK. AIRCOM International Ltd registered in England No. 3052022. VAT number 811 5323 68. Save a tree. Don't print this e-mail unless it's really necessary -- View this message in context: http://osgeo-org.1803224.n2.nabble.com/An-issue-about-using-GDALWARP-to-do-the-NTv2-transformation-tp5838904p5859107.html Sent from the GDAL - Dev mailing list archive at Nabble.com.
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