Le mardi 27 mai 2014 13:10:05, Marcel Korn a écrit : > We use geotif with units=seconds quite a lot. > > I found that running : > gdalwarp -t_srs <srs-def> <input path> <output path> > > 1. If target srs_def is a prj file with EPSG code for GCS WGS84 and units= > degree and my input file is a geotiff with GCS WGS84 and units= Seconds - > the output file is a "normal" geotiff with GCS WGS84 and units= degree. > 2. If target srs_def in a prj file with EPSG code for GCS WGS84 and units= > SECONDS and my input file is a geotiff with GCS WGS84 and units= degree - > the output is a geotiff with the units undetected correctly. > In order to correct the output file I used ArcCatalog and set the units to > seconds. > After the correction the file (and the header was ok). > Note: the prj must include authority = EPSG and the code (in this case > 4326) otherwise the geotiff is produced as Custom CS and it may or may not > be identified correctly and fully by apps. > Also note that with default units you can run gdalwarp with EPSG:4326 > instead of the prj file. > > It seems like there is a functional program bug since GDAL reads > non-default units OK but cannot produce a geotiff with seconds. Something > similar will probable happen with UTM PCSs if the target is feet instead of > meter (the default). > > I would like to know if somebody else found this problem and how he solved > it. > Of course, I wait to get confirmation it is a bug or maybe I did something > wrong. > If it is a "new bug" I woułd like to know what can I do to advance the > solution for it. > > This bug reminds me of a very old ArcMap bug that manifests itself when you > open a polygon or a raster with non-default units like second. If this is > the first item you open, the units are not read correctly until you reload > the GCS into the Data Frame. And than you get Degrees...the logic (or the > lack of it) is similar. > > Best regards, > Moty
Marcel, could you open a ticket with all the elements to reproduce ? From a quick review, it would require some work in proj.4 to add support for angular units and in the GDAL interface to proj.4 to use it to/from WKT. Perhaps in the GeoTIFF driver too. I would note, that using EPSG:4326 in WKT with units != degree is something that calls for trouble. The equivalent of EPSG:4326 with units = seconds is not EPSG:4326 You can contract a GDAL service provider if you want that topic to go forward. Best regards, Even -- Geospatial professional services http://even.rouault.free.fr/services.html _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev