[Gdal-dev] how to read SRTM files

[Vincent Schut]

There has been some postings on this list before about this topic. A google 
search on 'gdal srtm' will probably give you these.
Shortly, the hgt files are simple binary data, but can easily be 'translated' 
into a BIL file (which can be opened by GDAL) by generating the apporpriate 
(text file format) header file. You will find the exact answer on how to do 
this in the earlier postings on this list.

Good luck!

Vincent.

On Monday 13 December 2004 21:54, Ethan Alpert wrote:
> Looks like you're grabbing the "unfinished" data.
>
> >From the Documentation directory:
>
> ftp://e0dps01u.ecs.nasa.gov/srtm/Documentation/QuickStart.txt
>
> "Height files have the extension .HGT and are signed two byte integers.
> The
> bytes are in Motorola "big-endian" order with the most significant byte
> first,
> directly readable by systems such as Sun SPARC, Silicon Graphics and
> Macintosh.
> DEC Alpha and most PCs use Intel ("little-endian") order so some
> byte-swapping
> may be necessary. Heights are in meters referenced to the WGS84 geoid.
> Data
> voids are assigned the value -32768."
>
> You're going to need to do some processing before you can use these
> files.
>
> -e
>
>
>
> -----Original Message-----
> From: gdal-dev-bounces at xserve.flids.com
> [mailto:gdal-dev-bounces at xserve.flids.com] On Behalf Of Eduardo Patto
> Kanegae
> Sent: Monday, December 13, 2004 11:42 AM
> To: freegis-list at intevation.de; gdal-dev at remotesensing.org
> Subject: [Gdal-dev] how to read SRTM files
>
>
> Hi folks,
>
> I'm downloading SRTM NASA ziped files from
> ftp://e0dps01u.ecs.nasa.gov/srtm/South_America/ but I saw that I don't
> know this file format(.hgt)
>
> runnig "gdalinfo" one .hgt file I only got:
>
> ERROR 4: `N01W050.hgt' not recognised as a supported file format.
>
> GDALOpen failed - 4
> `N01W050.hgt' not recognised as a supported file format.
>
> Or my GDAL tools is missing something?
>
> Is there any free software that can read this files?
>
> thanks