New instruments for geological photo-interpretation and mapping

Abstract

Aerial photography is now an integrated part of topographic mapping. Half a century ago photogrammetric methods revolutionised the production of topographic maps, mainly because all contour drawing and measuring of detaiIs were transferred from the field to the laboratory. Based on very few field observations, a detailed and very accurate topographic map can be drawn from aerial photographs by photogrammetric methods. Thus, for an area that would require many weeks of fieldwork to produce a satisfactory topographic map, the same result can be achieved in the photogrammetric laboratory in a single day. In addition, accuracy can be very high. For instance, for a map at the scaie 1:50000 an accuracy on the ground better than 0.5 m can be reached by photogrammetric methods.