[Tilecache] TMS question

[Klokan Petr Přidal]

Hi Guillaume,

You are comparing address of the tiles in Mercator (EPSG:900913) and
in Geodetic (EPSG:4326) TMS profiles. I guess your maptiler tiles are
in "mercator" profile. To set up TileCache for mercator read this post
from Chris:
http://crschmidt.net/blog/archives/311/using-tilecache-with-google-maps-and-virtual-earth/

Here are same examples (proving the url is the same for both MapTiler
and TileCache):

TMS "geodetic" (EPSG:4326) profile - examples:

- http://labs.metacarta.com/wms-c/tilecache.py/1.0.0/basic/4/16/12.png
from http://www.tilecache.org/ website.
- http://staremapy.mzk.cz/naturalearth/4/16/12.png
from http://staremapy.mzk.cz/naturalearth/openlayers.html

TMS "mercator" (EPSG:900913 or EPSG:3857) profile - examples:

- http://hypercube.telascience.org/tiles/1.0.0/google-tiles/8/40/167.png
from http://crschmidt.net/mapping/google-tilecache.html
- http://www.klokan.cz/projects/gdal2tiles/overlay/8/40/167.png
from http://www.klokan.cz/projects/gdal2tiles/overlay/openlayers.html

This mashup shows different tile names for mercator tiles:
http://www.maptiler.org/google-maps-coordinates-tile-bounds-projection/
TMS Mercator is the default output of gdal2tiles/maptiler.

Best regards,

Klokan Petr Pridal

>> You're comparing an EPSG:4326 to a EPSG:900913 map... and thinking they'll
>> have the same tile IDs? Is that what you're asking?
>
> Did I ? My confusion must invade my postings too then !
> Here's what I'm trying to do exactly :
> I have a huge gdal2tiles cache (EPSG:4326) over France, and I retrieve
> the tiles from it throught standard TMS requests.
> I have a TileCache of a WMS layer in EPSG:4326 and I want to overlay it
> to the previous.
> I thought, kindly, that using the same TMS request (i mean z/x/y.png) on
> TC would send me back the correct tile. But it doesn't. At all.
> Here is my Tc layer's definition :
> type=WMS
> url=some_url
> layers=my_layer
> extension=png
> srs=EPSG:4326
> extent_type=loose
>
> I can't guess where the problems comes from...
>
> Thanks for your help
>
> Guillaume
>
>>
>> -- Chris
>>
>> > Regards
>> >
>> > Guillaume
>> >
>> >
>> > Le lundi 11 janvier 2010 à 13:33 -0500, Christopher Schmidt a écrit :
>> > > On Mon, Jan 11, 2010 at 03:42:35PM +0100, Guillaume Sueur wrote:
>> > > > Hi,
>> > > >
>> > > > I'm wondering about the TMS grid used in TC. The request I see here
>> > > > (http://labs.metacarta.com/wms-c/tilecache.py/1.0.0/basic/5/32/23.png)
>> > > > doesn't match with what I see there
>> > > > http://www.maptiler.org/google-maps-coordinates-tile-bounds-projection/
>> > > > for that area (north-east spain).
>> > > >
>> > > > Actually, does TileCache follow a specific TMS grid ?
>> > >
>> > > Not sure why you'd expect TMS and Google to be the same; Google is indexed
>> > > from the top left corner, TMS from the bottom left.
>> > >
>> > > Regards,
>> >
>> >
>> > _______________________________________________
>> > Tilecache mailing list
>> > Tilecache at openlayers.org
>> > http://openlayers.org/mailman/listinfo/tilecache
>>
>
>
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>

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