Downloadable layers for GPS

Make a data-transfer available on common GPS units. If one fx. is looking for a new house. As he drives around in an area he can download a map-layer with all the locations and data for houses for sale. He can then get an impression of that area by following auto-calculated routes that present him for all the available houses, their pictures, prices and other details – on his own car-gps!

Tourists could also profit from such a technology. Taking downloadable tours with videos or informations spoken to them as they visit the nice places ‘live’, maybe by car, maybe by bike or whatever.