Local Reference Systems

You can also use other coordinate systems. If you are not using Longitude, Latitude or UTM, the fixed location can be based on the relative distance between a fixed location on the earth and a point in the cave. This type of fixed location can be anything like a telephone pole, fence post, building corner, a land surveyor’s mark, a section corner, a bench mark etc. Another way of creating your own reference system is to take measurements from a topo map.