Roughly map the topology of the ground in the background of a photo, then use clever algorithms to match that topology with real world maps of terrain.
Automatically match iconic buildings to those in a database.
Have a list of features that are different from nation to nation, or region to region, and match them. Electrical outlets, road signs, road markings, fire hydrant colors, and match them automatically.
Have a list of different geology. Light coloured rock in this region, reddish soil in that region, very flat terrain, very undulating terrain.
This is what comes to mind in one minute of thought. None of these would be effective on their own, but combined you could probably get surprisingly close.
Automatically match iconic buildings to those in a database.
Have a list of features that are different from nation to nation, or region to region, and match them. Electrical outlets, road signs, road markings, fire hydrant colors, and match them automatically.
Have a list of different geology. Light coloured rock in this region, reddish soil in that region, very flat terrain, very undulating terrain.
This is what comes to mind in one minute of thought. None of these would be effective on their own, but combined you could probably get surprisingly close.