以數值地形圖和GIS資料計算都會區航照像片外方位參數之實用策略

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

許志彰(Chih-Chang Hsu) ； 廖揚清(Yang-Cheng Liao)

《航測及遙測學刊》 11卷1期 (2006/03) Pp. 69-79

https://doi.org/10.6574/JPRS.2006.11(1).6

摘要

都會區新舊建物替換的頻率高，因此地圖更新的需求也相對較高。使用航空攝影測量進行地圖更新的首要工作就是求算像片的外方位參數。因此本研究試圖利用舊有的數值地形圖和地理資訊系統的資料來解算像片的外方位參數。選取能夠明顯辨識的房屋角點代替航測標，則可以免去外業控制測量的程序，雖然屋角點的坐標精度不如以全球定位系統衛星測量得到的航測標，但大量的人工建物屋角點如同大量的地面控制點，均勻分佈在整張影像上，提供多於航測標數倍的觀測量，不僅可降低航測製圖的成本，也能夠提升成果的可靠度，彌補房屋角點坐標精度的不足。為了測試本研究提出的方法是否能夠有效應用於台灣都會區的局部地圖更新，自原航照影像中選取了數個子影像，分別針對不同的屋頂面類型進行實驗與分析，包含平屋頂、山形屋頂和女兒牆屋頂。經實驗證明，利用舊有的數值地形圖和地理資訊系統資料所求算得到像片外方位參數，成果和精度都比直接人工單像量測的成果更接近解析製圖儀的成果，且能滿足1/1000地形圖的製圖規範。

關鍵字

數值地形圖 ； 局部更新 ； 機率鬆弛法 ； 外方位參數 ； GIS資料

並列摘要

The large-scale maps of built-up area are of special interest if they are to be revised or supplemented with new themes. The very first procedure for map revision is obtaining the exterior orientation. In this research, database information, including a digital map and GIS data, is used for exterior orientation. 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, several sub-images are abstracted from the original aerial image over urban area, including rectangular buildings with plat roofs, gable roofs and roofs with parapets. The 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.

並列關鍵字

digital map ； local revision ； probabilistic relaxation ； exterior orientation parameter ； GIS data