Aargh. Sorry; I assumed way too much.
I'm not taking photos with the iPad. They would be geotagged already (although not sure if that's true if in Airplane, mode etc.).
I'm not syncing to a camera. Maybe Eye-Fi would do that; dunno.
I'm not interested in a GPS app that records waypoints and then syncs later on with a computer and a roll of imported photos. Have lots of ways of doing that now.
I want to import a photo to an iPad (raw would be nice) and in addition to editing it I'd like to geotag it. Even if the metadata is messed up (date on camera wrong, etc etc). By just finding the location on a map. As one can do in numerous computer applications. But on an iPad.
I can manually enter coordinates in the metadata, but that's a bit of a pain with the limited cut and paste of an iPad.
And BTW the built-in GPS's in cameras I've seen aren't as useful as a logger and the software. Some can eat up your battery. Some GPS apps also lag on geotagging because they insist on continually running to make a track rather than simply being switched on and off.
I just don't have much use for geotagging most photos; I only do it occasionally and hence the need for just the map-to-saved-photo workflow. Did this all the time with "Assign location..." in Aperture.