Hi Even, On Mon, Jan 27, 2020 at 1:45 AM Even Rouault <[email protected]> wrote: > Hi Markus, > > I've found some doc about this .jgwx in > http://resources.arcgis.com/en/help/main/10.1/index.html#//009t00000028000000 > So this is a ESRI specific thing > """Starting at ArcGIS 9.2 SP2, if the transformation cannot be expressed as a > world file, the Update Georeferencing command on the Georeferencing toolbar > writes the transformation into the .aux.xml file and also writes an > approximate affine transformation into a text file or a world file with an x > on the end of the extension name. [...]. Keep in mind that this is not an > exact transformation; it is only an approximation.""" > > So it might not be always relevant to report the content of the .jgwx as a > geotransform. Or if we did, we should probably add some metadata like > APPROXIMATE_GEOTRANSFORM=YES
I see, thanks for investigating. > > Using the graphical GPC tool of GRASS GIS > > (https://grass.osgeo.org/grass78/manuals/wxGUI.gcp.html) > > and exporting the map to GeoTIFF + gdal_translate to JPG with World > > file I obtained a quite similar result with working geotransform: > > How does this tool manage to create a geotransform frmo this file ? What it does is that it writes a POINTS file which is specific to https://grass.osgeo.org/grass78/manuals/i.rectify.html > The .aux.xml file does contain a GeodataXform ESRI specific element. GDAL just > extract this in the xml:ESRI metadata domain, but doesn't do further use of > this. Here it could potentially report the GCPs in it as GDAL GCPs. I've > grepped in GRASS source code to see if it has specific code to extract GCPs > from GeodataXform, but I can't find anything. So this is quite mysterious to > me. Sorry for the misunderstanding: I used to GRASS GIS' g.gui.gcp to generate GPCs from scratch, interactively. This graphical tool let's you assign X,Y to E,N, then it uses i.rectify (https://grass.osgeo.org/grass78/manuals/i.rectify.html) to georectify all images in the source imagery group. Eventually I exported to file using r.out.gdal. Best, Markus _______________________________________________ gdal-dev mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/gdal-dev
