You need to know the coordinate system you are using, then maybe these links will help http://spatialreference.org/ref/epsg/27593/ http://fr.wikipedia.org/wiki/Syst%C3%A8me_de_coordonn%C3%A9es_(cartographie) Bruce Dne 2.11.2012 18:10 "cawa sorix" <cawa.sorix@gmail.com> napsal(a): ... and I'm not a cave diver. Hi all, I try to put my cave centerline on google maps, I generated the kml file without issue. But I don't know the espg code for google maps, I tried a lot of them, but I'm always on the sea, I try to convert to an other system, always on the sea... For example my fix point is in Lyon (France) on google maps, but with my kml file I'm not at the right location. Do you know the ESPG code for google maps ? or how to put google maps espg on therion ? I put cs espg:4326 fix P-0 45.775643 4.85397 Thank you Laurent.