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<font style="font-size: 16pt;" size="4">----I HAVE OBTAINED THE SOLUTION----</font><br>Hello everybody:<br><br>I had one problem (read below) with a Geographic Transformation. I tried multiple choices but anything worked.<br><br>I thought that I get the solution when tried this way: <br>ogr2ogr -s_srs "+proj=utm +zone=30 +ellpse=intl +towgs84=-84,-107,-120,5,6,3,18 +units=m +no_defs +wktext" -t_srs EPSG:3035 OUT.shp IN.shp<br>but the adjustment between SHP and the map was still wrong. I get the Seven-parameter transformation from: <a href="http://www.colorado.edu/geography/gcraft/notes/datum/datum_f.html" target="_blank">http://www.colorado.edu/geography/gcraft/notes/datum/datum_f.html</a><br><br>Ultimately I read some advice and I tried a grid:<br>ogr2ogr -s_srs "+init=epsg:23030 +nadgrids=./PENR2009.gsb +wktext" -t_srs EPSG:3035 OUT.shp IN.shp<br>This grid are in NTV2 format and contains the longitude and latitude increase between ED50 and ETRS89 datums.<br><br>I get this grid from: http://www.ign.es/ign/layoutIn/herramientas.do<br><br>Thank you everybody for your advice. Hope this helps.<br><br><br>
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{font-size:10pt;font-family:Tahoma;}</style><font style="" color="#000000"><br><font style="font-size: 16pt;" size="4">----INITIAL PROBLEM----</font><br></font>
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</style><font style="" color="#000000">Hello everyone!!</font><font style="" color="#000000"><br></font><font style="" color="#000000"><br></font><font style="" color="#000000">I </font><font style="font-size:10pt" class="ecxApple-style-span" color="#000000" size="2"><span class="ecxApple-style-span" style="font-size:13px"><font style="" class="ecxApple-style-span">converted </font></span></font><font style="" color="#000000">a DXF file to a shapefile using 'ogr2ogr' command. When I use the "-t_srs" parameter the system </font><font style="font-size:10pt" class="ecxApple-style-span" color="#000000" size="2"><span class="ecxApple-style-span" style="font-size:13px"><font style="" class="ecxApple-style-span">tells</font> </span></font><font style="" color="#000000">me: "Can't transform coordinates, source layer has no coordinate system. Use -s_srs to set one."</font><font style="" color="#000000"><br></font><font style="" color="#000000"><br></font><font style="" color="#000000">The command '-s_srs' override source SRS. What is the difference between '-s_srs' and '-a_srs' command? What is the exact meaning of "Assign an output SRS"? I don't understand that.</font><font style="" color="#000000"><br></font><font style="" color="#000000"><br></font><font style="" color="#000000">I use the '-s_srs' command and when I overlay the shapefile over a map,</font><font style="font-size:10pt" class="ecxApple-style-span" color="#000000" size="2"><span class="ecxApple-style-span" style="font-size:13px"><font style="" class="ecxApple-style-span">the adjustment isnīt very good with the map</font></span></font><font style="" color="#000000">, so I must make a geographic transformation. I get that transformation thanks to 'ProjectionUtility' (ArcView). Its name is Geocentric[9603], ED_1950_TO_WGS_1984_13, POSC Code:8045.</font><font style="" color="#000000"><br></font><font style="" color="#000000"><br></font><font style="" color="#000000">I need to make this transformation automatically. How can I make this transformation using 'ogr2ogr'? Is it possible?</font><font style="" color="#000000"><br></font><font style="" color="#000000"><br></font><font style="" color="#000000">Thank you very much</font><br><br> </body>
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