I created a patch which adds geotagging to the image display, below the image a map view with a marker is displayed if the picture is already geotagged. The size of this map view can be enlarged if necessary as it is rather small initially. A nearest address is shown if available.
In admin mode you can add (or modify) geotags, either by direct coordinate input, search by address, or by copying the location from th image before or after the actual one (and probably modifing this location a little bit).
Map display and related stuff is based on the google maps API 3.0, PHP access to GPS tags is done via the PEL library which is also included in the patch.
See http://www.algepop.net/PHPgraphy-0.9.13b/ for more details and possibly newer versions of the patch.
TODO: Currenly it works for coordinates in the eastern hemisphere only.
TODO: an overview map containg all locations of a subgallery.
Albrecht Gebhardt <email@example.com>