One way is to make different geiger counter on your profile with different locations. But on your unit, you have to change the geiger counter ID when sending data online with WiFi. Another way is for 510+ it has GPS and GPRS, I need to confirm this though if you can see the tracks of data on the map.
This map is for charting readings over time at fixed locations. A map that shows location-based readings at fixed points in time is Safecast.org on the Safecast layer. They also have a few real-time fixed sensors like GCMap.com.