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

Joaquim Luis jluis at ualg.pt
Mon Nov 14 12:23:23 EST 2011


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


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