Google Maps API Tutorial

APIv2 supports the old v1 documented commands (except openInfoWindowXslt) as well as the new v2 syntax.

If you already have a working v1 map that doesn’t use any undocumented features, then you can just change the version number when you load the API code and it may well work the same.

One significant source of incompatibility is that you must perform a map.setCenter() before adding any overlays.