[gdal-dev] requesting tiles according to my dteds data c++

[Saâd HESSANE]

DTED files are really simple to undertand. A DTED CD-ROM is organized like
this :

   - *dted (folder)*
      - *D### (folder)*
         - H##.dt# (file)
         - H##.dt# (file)
         - ...*
         *
      - *D### (folder)*
      - *...
      *
   - *gazette (folder)
   *
   - *text (folder)
   *
   - dmed (file)

# : digit
D : The direction of the tiles E for East and W for West
H : The hemispher of the tile : N for North and S for South


A DTED file represent data elevation of a square of 1°x1°. So the folder
"e055" contain dted files that have longitude 55E. If the folder contain
the file "n33.dt0", that mean the file contain data elevations of a 1°x1°
square starting at 55E 33N (ending at 56E 34N).

Note about DTED specification :

   - The DTED specification don't tell if the lettre have to be in capital
   lettre or not. So you can have "n33.dt0" or "N33.dt0". Be careful with that.
   - The specification don't tell to have contigu file or folder. So you
   can have a folder E055 and E060 without the folder between 55 and 60.


I hope I answerd your question.





2012/4/10 len lee <noura.salem.shamsi at gmail.com>

> hello;
> i downloaded dted data dt0 from raster roam website and there are 3
> folders e055, e056 and e057 and within each folder there are 3 dted files
> and i guess each dted file here represent a tile within my terrain. now
> what am trying to do is requesting the terrain tiles according to my dted
> data .. any idea how can i do that with gdal lib?
> i tried this:
> poDataset = (GDALDataset *) GDALOpen( "
> http://tile.openstreetmap.org/15/23687/15190.png", GA_ReadOnly );
>
> to request a specific tile from openstreetmap server but as you can see i
> need to know the exact coordinate system for that tile ...
>
> please all what i need is to understand the process of requesting the
> tiles according to my dteds files;
>
> i will appreciate any help;
> thanks in advance;
>
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> gdal-dev at lists.osgeo.org
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