Global positioning system: An effective way to map a small area or catchment

Abstract
The Global Positioning System (GPS) is an established method for establishing high accuracy horizontal and vertical control points over large areas. Recent improvements in receiver technology, differential surveying and software have made the use of GPS technology more practical for smaller projects. This paper compares different GPS methods with occupation times of 2 s, 2 min and 12 min using an existing control network, and the gathering of topographic data from a difficult field site. Two examples are given, one in East Texas, demonstrating the speed and accuracy of different techniques, and the other in the Quantock Hills in Somerset.