The basis for map dowsing is that everything vibrates to its own frequency, that we live in a primordial soup of frequencies or information, and that these frequencies are detectable. Or put more simply everything is out there in the vibes and is detectable by dowsing.
Since everything has its own special vibration or frequency, it is possible to sense substances from any place on the planet. From Maxwell’s theorem we learn that wave forms are direct, instantaneous, absolute and travel faster than light. Thus we can dowse, sense, pick up, or identify almost anything from anywhere. It behooves us to stay in the present, focus our intentions clearly and practice until we are able to discern these frequencies.