[Tilecache] tilecache, mapnik & projection issue

[Christopher Schmidt]

On Thu, Mar 27, 2008 at 05:38:29PM +0000, Xin wrote:
> I am having problems getting OpenLayers to use tilecache and Mapnik.
> 
> The image /1.0.0/google-tiles/5/17/18.png from Tilecache, is different to
> the image /5/17/18.png generated from generate_tiles.py.
> 
> Is the way generate_tiles.py saves tiles compatible with Tilecache?

I'm assuming that you're getting something that's 'flipped' over the
equator. It's likely that you want the "tms_type=google" option on your 
TileCache layer if you *really* want the 'identical' tile IDs...


> My map is in Google projection.
> 
> My OpenLayers Tilecache layer:

1. Don't use a TileCache layer unless you're pre-generating *all* of the
   images you could possibly use: use a TMS layer. 
2. If you *do* use a TMS layer, you don't have to add tms_type=google,
   you can simply not override getURL and it should work fine.
3. If you do chose to go with the non-standard "google" tile scheme,
   you can still use a tms layer with a getTileURL function, and be
   inline with all other OSM usage.
 

Regards,
-- 
Christopher Schmidt
MetaCarta