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Hello Jukka,<br>
<br>
On 03/12/14 10:13, Jukka Rahkonen wrote:<br>
<span style="white-space: pre;">> Homme Zwaagstra <hrz
<at> geodata.soton.ac.uk> writes:<br>
><br>
>><br>
>> Hello,<br>
>><br>
>> I've come up against a problem with `gdalbuildvrt` taking
a long time to <br>
>> create<br>
>> a VRT when it is passed a large number of source
datasets. I am trying <br>
>> to create<br>
>> a VRT file for a zoom level in a TMS structure containing
JPEG tiles. The<br>
>> command I'm using is:<br>
>><br>
>> gdalbuildvrt output.vrt `find ./tiles/18 -iname *.jpg
-printf "%p "`<br>
>><br>
>> where the number of tiles is:<br>
>><br>
>> $ find ./tiles/18 -iname *.jpg | wc -l<br>
>> 767104<br>
><br>
> I would say that you are doing all wrong thing. First, the
jpeg tiles in<br>
> tile service directory structure are not referenced with
world files (.jgw)<br>
> or anything and your .vrt file would be useless.</span><br>
<br>
Sorry, I should have said: each of the JPEG tiles has an
accompanying<br>
`*.aux.xml` file. The files were created under the hood by GDAL
using<br>
<a class="moz-txt-link-rfc2396E" href="https://github.com/geo-data/cesium-terrain-builder#ctb-tile"><https://github.com/geo-data/cesium-terrain-builder#ctb-tile></a>.<br>
<br>
<span style="white-space: pre;">> The right thing to do is to
study the file naming schema that the cache is<br>
> using. When the schema is known the right tile can be found
directly because<br>
> the logic knows how the tile directory structure is like and
which names are<br>
> used for the tiles. If it is an OSGeo TMS schema it is
described here<br>
>
<a class="moz-txt-link-freetext" href="http://wiki.osgeo.org/wiki/Tile_Map_Service_Specification#TileMapService_Resource">http://wiki.osgeo.org/wiki/Tile_Map_Service_Specification#TileMapService_Resource</a></span><br>
<br>
The on-disk tiling scheme conforms to<br>
<a class="moz-txt-link-rfc2396E" href="http://wiki.osgeo.org/wiki/Tile_Map_Service_Specification#global-mercator"><http://wiki.osgeo.org/wiki/Tile_Map_Service_Specification#global-mercator></a>
with<br>
the tile directory structure matching `{zoom}/{x}/{y}.jpg`.<br>
<br>
Best regards,<br>
<br>
Homme<br>
<br>
<span style="white-space: pre;">><br>
> If it is using the Google/Bing tile naming schema then you
can find examples<br>
> here <a class="moz-txt-link-freetext" href="http://www.gdal.org/frmt_wms.html">http://www.gdal.org/frmt_wms.html</a>. But if it is a
GeoWebCache tile<br>
> cache you may be out of luck because I haven't seen so far
any configuration<br>
> file that would make GWC tilecache usable for GDAL.<br>
><br>
> -Jukka Rahkonen-<br>
><br>
> _______________________________________________<br>
> gdal-dev mailing list<br>
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<br>
<br>
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