ABSTRACT
Distances may be measured by five methods: tape, optical, electromagnetic, ultrasonic or GNSS. The method used on any particular job depends upon the number and size of the distances to be measured, the nature of the ground, the accuracy required, the time available, and the availability of suitable equipment. For all but the smallest or largest tasks, electromagnetic distance measurement (EDM) is the simplest choice for terrestrial measurement. GNSS measurements provide interpoint distances over any distance and without the need for intervisibility, but the procedure is rather more complex.
