Development in digital photogrammetric systems for topographic mapping and GIS/LIS applications
Author(s)/Corporate Author (s)United Nations. Economic Commission for Africa;
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This paper sets out the current situation in the development of digital photogrammetric systems (DPS) as applied to the field of topographic mapping and GIS/LIS applications. It includes the devices used for input to and the output from such a system, as well as its main element, the digital photogrammetric workstation (DPW). The various sources of digital image data and the volumes of such data which have to be handled are first discussed in some detail This discussion is followed by a review of the photogrammetnc quality scanners currently available on the market Next, the hardware aspects of the DPW are discussed including Processors, data display, stereo-viewing and measuring/positioning devices. A classification of present DPWsis then made and is accompanied by a table setting out the main characteristics of those systems which Te available commercially. The paper then goes on to discuss the algorithmic and software aspects of DPWs including the1 software modules developed for orientation, triangulation, map Compilation, DEM generation and ortho-image production. The final section deals with the output side of the DPS including a review of the various types of plotter that are available to generate hard copy maps and-ortho-images from the digital data produced by DPWs.