Many divers like to be able to visualize the GPS location of a specific dive. Especially on dive boats handling a device to correctly record GPS coordinates and writing them down is often hard. Companion app idea is to allow the diver to simply start a background process that records GPS locations at given intervals. The next time the iOS device has connectivity those timestamp / location pairs are uploaded to a webservice backend. The Subsurface desktop application can then download this data and map the GPS locations to dives that have been manually entered or downloaded from a dive computer. This allows the diver to have fairly accurate GPS locations for their dives without having to handle a device on the dive boat.