When an EMS unit is given a call they are told an address, cross street(s), sometimes a map page/number, and then UTM. What does the UTM (universal transverse mercator) number give them? It is normally just a 6-7 digit number. Is it meant to be entered on their computer system or is it a physical map? I can understand how a map page would correspond to a part of a mapbook showing the street but where does the UTM number fit in?