Generation of digital elevation model through aerial technique

Abstract

Unmanned Aerial Vehicle (UAV) system, nowadays, is highly utilized to solve problems in various applications across different fields due to its low-cost, safety, and its low flying altitude. With photogrammetric techniques and latest available aerial technology, it is possible to utilize UAV for generation of Digital Elevation Model (DEM) and subsequently, determination of elevation on various geomorphology. Previously, this is only possible through deployment of manned aircraft and metric camera which requires monumental cost. This paper reviews the applications and developments of DEM generation. Three main components are presented in this review: (a) a summary of conventional surveying methods to determine elevation, subsequently generate a DEM, (b) a summary of remote sensing methods to generate DEM; namely satellites, and airborne platforms, and (c) findings and future possibilities for further studies. The review reveals that traditionally, DEM is produced through ground surveying methods, traditional photogrammetry methods, and derivation of contours and elevation points from hardcopy topographic maps. The chapters discuss each of the methods and common DEM products derived from them. Most of the studies reviewed herein articulate the mechanism of triangulation which is a method to rectify the DEM to its local geographical and elevation coordinates. So far, only a relatively small number of detailed studies have been conducted on the DEM produced by UAV. From the findings of flying the UAV at 4 different altitudes of 50 m, 80 m, 110 m and 140 m; much more research on the identification of elevation through UAV-based imagery is required from different altitude of flight. Hence, it is possible to use UAV to identify elevation in small areas which has limited project budget and time constraints.