ASSESSMENT OF TOPOGRAPHIC MAPS PRODUCED BY DIGITAL PHOTOGRAMMETRIC WORKSTATION | ||
| The International Conference on Civil and Architecture Engineering | ||
| Article 33, Volume 7, 7th International Conference on Civil and Architecture Engineering, May 2008, Pages 337-347 PDF (906.14 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/iccae.2008.45516 | ||
| Authors | ||
| MOUSSA O. M.1; RAGAB A. F.2; KHEDRE N. A.3 | ||
| 1Professor, Chair of Civil Engineering, Military Technical College, Cairo, Egypt. | ||
| 2Associate professor, Dpt. of Public Works, Ain Shams University, Cairo, Egypt. | ||
| 3Colonel, Syrian Defense. | ||
| Abstract | ||
| Topogeaphic map can be considered as an essential initial product for most of large engineering projects. Hence, increasing the efficiency and quality of these maps is a main issue of any surveying works. Many methods are considered in the production of topographic maps, according to the required accuracy, available instruments, afforded time, and involved personnel. The history of topographic map production by photogrammetry is not very old, only about half a century, due to its great efficiency and advantage especially in inaccessible and mountaneous areas. Today, photogrammetry has been vastly broadened to include the use of data from sensors utilizing other portions of the electromagnetic spectrum, in additional to the conventional photography, for many applications. Also, as a result of the rapid development of computer technology and software, assessment of the accuracy of the topographic map produced by applying the principle of digital photogrammetric workstation is the main scope of the current investigation. In order to achieve this objective, aerial panchromatic photos have been taken at a scale of 1:15000 for a certain hilly study area, and scanned at different resolutions. Leica photogrammetry suite (LPS) digital software was used to perform this work with reasonable accuracy. The final resulted values as discrepancies of some selected check points, root mean square errors, total image unit-weight RMSE, and standard deviations of the automatic generated tie poits shows that 2117 dpi resolution , which equivalent to an image coverage 12 μm, gives the less error values than the other adopted resolutions and with an absolute optimistic accuracy. In addition, the topographic map, presented as a layer of spot points, resulted from this resolution will be compared with the available base topographic map for the same study area produced from analytical stereoplotters device, by using special map projection software for unifying the coordinates of both analytical and digital map. From this comparison, it can be found that, about 75% percent of the resulted points passed on contour’s reference topographic map, which indicate the efficieny of the topographic maps produced by digital photogrammetric workstations. | ||
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