Photogrammetry : an evaluation

Abstract

Photogrammetry, a system of measuring data recorded on photographs, has a large number of applications mainly in those sciences that depend on reliable geometric measurements of physical quantities in a fixed or transitory state. In Malta, photogrammetry is being used for topographic mapping which is its widest application. Like other sciences, photogrammetry is continuously experiencing a tremendous advance in its technological aspects especially in instrumentation. The following write-up is intended to give the reader a brief introduction to photogrammetry and as it is being applied in Malta. Apart from giving some of the historical highlights and how this interesting science evolved, the main subject to be treated is the geometry of aerial photographs and the behaviour of their scale with the variation of the terrain being studied. This important variable affects directly the photogrammetric process, both in speed and accuracy of the final product. In the final chapter, examples are given of scale variation due to terrain irregularities in Maltese urban areas and the problems which crop out and methods of how this problem may be minimised. Finally, some of the parameters which are taken in consideration in flight planning to choose the photographic scale are discussed.