ok, thank you for these infos.
I’m not very use of ruby scripts but i’ll try to do my best.
There’s just something hard for me to understand.
There is lots of ways to make your maps appear on openlayer, now i’m using the Tilecache projection witch takes .png tiles on my local server and do all the work (the files are keep in directories like “map/1/2/1.png” which means “map/zoom/x/y .png”) .
My question is : do i have a possibility to make export work with this projection, or do I have to change my projection and use Mapnik generated images?
By projection you mean e.g. EPSG:4326 that tells you how what the meter/pixel ratio is, right?
I don’t know how tilecache operates but I guess it’s downloading tiles from Openstreetmap. In that case you should use the MapOf script (which is PHP).
If you have a copy of database then it 's the same as the main site. The Openstreetmap site use the Mapnik map drawing library to export what it has in the postgreSQL database it will set a projection like this: