[gdal-dev] Reading SRTM30 grids 'at distance'

Frank Warmerdam warmerdam at pobox.com
Mon Nov 14 13:47:54 EST 2011


Joaquim,

I can't think of a way to do this with an ESRI .hdr and raw file.
However, you could create a VRT file for each tile with the .VRT
file living locally, having the georeferencing and raw data layout
and referring to the actual raw data via a /vsicurl filename.  The
VRT docs cover how to describe a raw file in VRT.

Best regards,


On Mon, Nov 14, 2011 at 9:23 AM, Joaquim Luis <jluis at ualg.pt> wrote:
> Hi,
>
> I made a nice little tool for Mirone where one can very easily mosaic either
> several flavors of SRTM grids or satellite images from Bing servers.
> My question is about the SRTM30 grids (30 arc minutes) that are available
> here (SRTM plus)
> ftp://topex.ucsd.edu/pub/srtm30_plus/srtm30/data/
> which I would like to be able to access directly with the vsicurl mechanism.
> The trouble in this case is that those grids are raw files without any
> header file. When we have them on disk the simple solution is to create a
> esri .hdr header from the information extracted from the file name. However,
> this logic does not work for files seating in the Web because the file and
> the header won't be located next to each other. The same occurs if one has
> those files compressed. In this case the header file cannot be assumed to be
> stored inside the .zip file and the vsizip mechanism will fail for exactly
> the same reason.
> My question is than, if there is a mechanism to send the header info to the
> GDAL library and thus pretend that file and header leave side by side? Note
> that I want to do this programmatically so need for an already existing
> ready to use solution.
>
> Thanks
>
> Joaquim
> _______________________________________________
> gdal-dev mailing list
> gdal-dev at lists.osgeo.org
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>



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