[gdal-dev] concatenated VRT file

[Jan Hartmann]

Thanks Eli, but this is not what I am trying to do. I have to create 
hundreds of VRTs, all the same except for the one <geotransform> line. I 
would like to to this without making physical copies of the whole file, 
but with some sort of symbolic link to a central VRT-file, and just add 
the geotransform information for each individual file. Perhaps it isn't 
possible; in that case I'll hard-copy the whole bunch.

Jan

On 6-8-2013 18:18, Eli Adam wrote:
> On Tue, Aug 6, 2013 at 2:21 AM, Jan Hartmann <j.l.h.hartmann at uva.nl 
> <mailto:j.l.h.hartmann at uva.nl>> wrote:
>
>     Not sure if this is possible, but perhaps someone here knows a trick.
>
>     I use a VRT file as an index to a large set of detailed, tiled
>     scans of the Netherlands, built with gdalbuildvrt. I recently
>     discovered how to transform this map on the fly, so that it 
>     exactly aligns to older maps in different coordinate systems. It's
>     just a matter of adapting the <geotransform> item in the VRT file.
>
>
> I'm not sure if this will work for what you are doing, but I change 
> the projection of VRT files with gdalwarp: gdalwarp -of VRT -t_srs 
> "+proj=omerc +lat_0=44.75 +lonc=-124.05 +alpha=5 +k=1 
> +x_0=134743.33241 +y_0=369139.02771 +ellps=GRS80 +datum=NAD83 
> +to_meter=0.3048 +no_defs +wktext" infile.vrt outfile.vrt
>
> Eli
>
>
>     So I can copy the VRT file for every old map, and adapt the
>     <geotransform> in each of them. This means that all VRT files will
>     be identical, except for the <geotransform> line. The VRT files
>     are quite large, because they cover lots of tiles. Can anyone here
>     think of a method to do this with one central VRT file, in which
>     only the <geotransform> line is plugged that is required for the
>     particular old map?  Something like a symbolic link to concatenate
>     the variable and stable parts of the VRT file?
>
>     Jan
>
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