Hi Mario, Il giorno ven, 06/05/2011 alle 12.56 +0000, mario santos serrano ha scritto:
> I converted a DXF file to a shapefile using 'ogr2ogr' command. When I > use the "-t_srs" parameter the system tells me: "Can't transform > coordinates, source layer has no coordinate system. Use -s_srs to set > one." -a_srs should be used to translate a source file which has no SRS definition (like DXF or SHP with no .prj file) into a georeferenced format: the original coordinates are not transformed, and an srs definition is associated to the target dataset. > 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. -s_srs can be used when to replace (override) the source file SRS definition, or to set it if a transformation with -t_srs is needed. You can only transform from one SRS to another one, that's why -t_srs will not work with DXF if you don't declare the DXF srs with -s_srs. > I use the '-s_srs' command and when I overlay the shapefile over a > map,the adjustment isn´t very good with the map, 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. > > I need to make this transformation automatically. How can I make this > transformation using 'ogr2ogr'? Is it possible? I'm just guessing 'cause I've never tried this. Check if ProjectUtility writes a .prj file; it should contain a WKT definition of the resulting dataset SRS. According to ogr2ogr doc, this WKT (or the name of the file containing it) can be passed to -t_srs or -a_srs. Try and let us know. Hope this helps Sig > > Thank you very much > > _______________________________________________ > gdal-dev mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/gdal-dev _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
