Hi, On Fri, Mar 13, 2009 at 9:18 PM, Even Rouault <even.roua...@mines-paris.org> wrote: > Yes, this is possible but you need to adhere strictfully to the DTED > specification. A DTED tile covers exactly a 1 degree x 1 degree area and the > corners coordinates must be aligned on integer. As far as I remember, DTED0 > has a 30 second x 30 second resolution below latitude 50°, 60'' x 30'' > between 50 and 70, 90'' x 30'' between 70 and 75, etc (read the spec). > > So you will have to produce several DTED files if your input area is over > several 1° x 1° square. You should use the -prjwin to just select the right > area for each tile, like : > gdal_translate -of DTED input.dem n40e2.dt0 -prjwin 41 2 40 3 > gdal_translate -of DTED input.dem n40e3.dt0 -prjwin 41 3 40 4 > etc.. > > With a little of scripting (Python for examle), you could automate that by > reading the extent of the source . > > You must be sure that your source input has the same resolution as the > produced DTED, otherwise you'll need to adjust it by specifying the right > destination size with -outsize 1201 1201 (below 50° latitude). > > I see in GDAL source tree that there's a (not compiled) utility that seems to > do you want. The main file is frmts/dted/dted_test.c, but it relies on the > other C files of the DTED driver. You would need to fiddle a bit with the > makefiles and the header to compile it (I see that some necessary symbols > might not be exported). It is moderately involved provided that you have some > experience with C.
This is a very nice recipe, thanks! > But if your third-party app supports 16bit GeoTIFF as a possible source for > DEM, it would be easier to translate to GeoTIFF. Wouldn't that lose elevation information? Regards. -- İsmail DÖNMEZ _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev