Le dimanche 17 juin 2012 18:24:29, Smith, Michael ERDC-RDE-CRREL-NH a écrit : > I have a large number of NITF JP2K files. These files have IGEOLO metadata > to the second accuracy so reprojecting these images leads to poor results. > The images also have rpc metadata and using the -rpc option in gdalwarp > reprojects them quite well. These files are source epsg:4326 and need to > be reprojected to epsg:3857 for display. > > I had orginally thought to just create a vrt for each ntf file with the rpc > information but a tileindex of the vrts is dramatically slower to display > in MapServer (for a 1:8000 scale area, from ~ 1 sec to over 10 min). It > does reproject correctly though. Obviously not practical. > > I then thought to reproject the vrts to an actual format (geotiff). The > problem is that the black bounds (which should be nodata but are just near > black areas) get expanded and aren't handled even when using the nearblack > utility on the resulting geotiffs. > > The best option (if possible) would seem to use the source nitf files but > force gdal to use the rpc information to reproject (without having to go > through the vrt process). Perhaps a CPL config option that could be set > inside mapserver?
Did you use the -dstalpha option of gdalwarp, so that the areas in the reprojected image that are not part of the source image are marked with a 0 alpha value ? -dstnodata could also do it. > > Other suggestions are welcome. > > Mike > > -- > Michael Smith > [email protected] > US Army Corps > Remote Sensing GIS/Center _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
