A Practical Strategy of Calculating Exterior Orientation of Urban Aerial Photos by Digital Map and GIS Data

• Main Authors: Chih-Chang Hsu, 許志彰
• Other Authors: Yang-Chang Liao
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/45519304154339805377

碩士 === 國立成功大學 === 測量工程學系碩博士班 === 92 === 　　The very first procedure for map revision is obtaining the exterior orientation. Up to now, for most general photogrammetry, the control surveys are taken by GPS surveying which is however a time-consuming task for local map revision over urban area. In this research, database information, including a digital map and GIS data, is used for exterior orientation. 　　The large-scale maps of built-up area are of special interest if they are to be revised or supplemented with new themes. The existing maps have sufficient and accurate information which could be used to find the orientation of the new images. It would save times using building’s corners instead of the control points. Although the accuracy of the building’s corners could not be as good as those control points, the uniform-located corners would provide a great quantity of observations which could hopefully increase the reliability. 　　To see if the applied method would work efficiently, nine sub-images are abstracted from the original aerial image over urban area, including rectangular buildings with plat roofs, gable roofs and roofs with parapets. After line feature abstracting, relaxation method is used to determine the class of each line features. Space resection is carried out through intersection points from proper line features. The experimental result shows that it is feasible to find exterior orientation by existing digital map and GIS data and would suffice the required accuracy for local revision over 1/1000 map, which is stipulated under 10% of the complement coordinates would be allowed to deviate 20cm exceedingly corresponding to the aero-triangulation points.