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

[Chaitanya kumar CH]

Noura,

First, note that osm tiles are presented in EPSG:900913 reference system.

The usual way of requesting the tiles is based on the extent coordinates.
GDAL's WMS driver[1] can be used to access it. For that you need an XML
file[2] specifying the service.

Once you obtain the coordinates like Saâd explained, convert them to
EPSG:900913 and use it obtain the tiles.

[1]: http://www.gdal.org/frmt_wms.html
[2]: http://www.gdal.org/frmt_wms_openstreetmap_tms.xml

On Tue, Apr 10, 2012 at 2:17 PM, Saâd HESSANE <saad.hessane at gmail.com>wrote:

> 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 mailing list
>> gdal-dev at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/gdal-dev
>>
>
>
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-- 
Best regards,
Chaitanya kumar CH.

+91-9494447584
17.2416N 80.1426E
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