14.1 INTRODUCTION

Almost all the survey methods mentioned in this book so far relate to individual survey observations and their subsequent use in survey computations. For example, in a conventional resection, observations are taken at one point to three other points and those observations along with the coordinates of the targets are used to find the coordinates of the instrument point. If a number of points were required the productivity rate would be only a few points per day at best and so to find the coordinates of many points by such a method would be slow and tedious in the extreme. Finding a series of control points with a traverse, or by using the least squares adjustment of a network, would be more productive.

The surveyor could then use a total station and data logger to collect a series of detail points more rapidly. Even so the data capture rate would depend upon the speed at which the surveyor could travel from point to point and even in the most favourable environment the data capture rate would not exceed a few hundred points per day. If it is not necessary for the surveyor to physically identify each point on the ground and/or it is not necessary to remain static at each point during data capture then the productivity rate can be improved.

Reflectorless EDM makes it possible to measure to a point without that point being visited, though details of the point still need to be recorded to make...