ELECTRONIC DISTANCE-MEASURING TECHNIQUES TO PROVIDE GROUND CONTROL FOR TOPOGRAPHIC MAPPING BY AERIAL PHOTOGRAMMETRY

Abstract

The aerial photogramuuetric methods have proved economical, speedy and easier as compared to the old classical methods to produce topographical maps, In all photogrammetric processes of map compilation certain basic horizontal and vertical ground control are required„ Although the density of this control can be drastically reduced by. aerial triangulation and block adjustment techniques;k hen certain minimum ground control is required. Besides these basic control points, photo control are also essential. In this dissertation the various electronic distance measuring techniques ues for providing photo-control are discussed assuming that the basic control exists. Trilateration has not been dealt with which is connected ° with the primary control. Description, characteristics, accuracies, limitations and, different models of short and medium range instruments which are suitable for our purpose have been treated in details. Shoran and Hiran, which are used in Canada for small-scale mapping and for providing primary geodetic control, bear a passing reference in this work.