Since HDRis are so linked to a specific location, it might be nice to show them on a map.
GPS coordinates could be stored in the node. They could be entered manually by the user, or even read from EXIF information.
If we want to take it a step further, we could also include a direction, so that we can show a little arrow on the map to indicate which direction the user is viewing.
Here are some useful links. Ignore that they are about Google Maps (which I wouldn't suggest using), just look at the EXIF tags that contain the GPS position & orientation.