地層下陷泛指地層表面發生向下沉降之現象，屬於長期且持續性的災害，容易造成對地表環境的傷害，如洪水氾濫及土壤鹽化等，為了有效地監測地層下陷的行為，減少其負面影響，故有必要進行多類型歷史資料的探討。傳統過去的監測方法以水準測量及設置監測井為主，得到的觀測資料為點位紀錄的形式，較無法突顯整體區域之下陷變化情形。本研究利用多時期航拍影像，透過數位攝影測量方法製作多時序的DEM資料，並藉由歷史觀測數據的蒐集分析，輔助還原下陷區域之下陷史，進而分析地層下陷在時間及空間上的變化。實驗區域以雲林縣內陸三個鄉鎮(元長、土庫、褒忠)為主要涵蓋範圍，透過多時序DEM比較的成果，可觀察發現短時期觀測資料其地表下陷趨勢較不顯著，而長時期觀測資料則呈現較明顯的地表下陷變化，且出現二個下陷中心分別集中於東北及西南方向，推測此二處地方可能存有某種人為因素而導致下陷情形較為劇烈。

Land subsidence, a surface motion downward relative to an elevation datum, is a persistent and continuous phenomenon. It may easily cause a land crisis, such as floods and salted land. In order to monitor the subsidence behavior and to reduce negative influences, it is necessary to recover the history of land subsidence using multi-sources historical data.Traditional surveying methods for land subsidence monitoring are based on leveling and the setting of monitoring well. These methods generates point-based observations, which hardly present the long-term phenomenon of land subsidence in the overall area.This study presents the idea of using multi-temporal aerial images to generate multi-temporal DEMs for retrieving the history of land subsidence. Meanwhile with the collection and analysis of relative historical data, it is helpful to discuss the subsidence situation not only in spatial domain but also in time domain.The test site is located in the inland towns of Yunlin county. Through comparing the DEMs, the estimation of land subsidence in the past can then be carried out. The result of short-term observation data is less significant than the one of long-term observation data. Besides, there exist two sinking centers in the direction of N-E and S-W area which may be as the consequence of some unavoidable artificial causes.

毛冠貴，”台灣西部沿海養殖地區轉型使用機制之研究”，農業經濟半年刊，72卷，pp.1-43，2002。
吳善薇，”應用雷達干涉法在彰化縣員林地區地層下陷研究”，國立中央大學，78頁，2005。
徐享崑、鄭昌奇、童慶斌、游忠信、陳均源、趙子澤及許澤善，”沖積扇地層下陷之預測方法”，第二屆地下水資源及水質保護研討會論文集，pp.235-246，1997。
柳志錫、杜富麗及洪偉嘉，”超抽地下水引起之地層下陷問題探討”, 工研院能資所，http://140.96.175.22/geosink/html/intro/Techpaper/tp44.pdf，2003。
柳志錫及黃鎮臺，”超抽地下水引起之地層下陷問題探討”，中國土木水利工程學會會刊，29卷，2期，pp.47-57，2002。
黃鎮臺及杜富麗，”臺灣地層下陷區的特性與防護技術探討”， 「地層下陷防治執行方案」暨「地下水觀測網整體計畫」九十一年度執行成果發表研討會，2003。
謝嘉聲及史天元，”以雷達干涉技術偵測地表變形之研究”，第二十一屆測量學術及應用研討會論文集，2002。
劉鴻喜，”臺灣地下水之研究”，臺銀季刊，14卷，3期，pp.218-253，1963。
盧玉芳，”以雷達干涉技術監測雲林地層下陷”，國立交通大學，106頁，2007。
Ackermann, F., “Practical Experience with GPS Supported Aerial Triangulation”, Photogrammetric Record, vol.:14(84), pp.861-874, 1994.
Ackermann, F., “Airborne Laser Scanning - Present Status and Future Expectations”, ISPRS Journal of Photogrammetry & Remote Sensing, vol:54, pp.64-67, 1999..
Axelsson, P., “DEM Generation from Laser Scanner Data Using Adaptive Models”, International Archives of Photogrammetry and Remote Sensing, Amsterdam, pp.110-117, 2000.
Maune, D.M., “Digital Elevation Model Technologies and Applications: The DEM Users Manual”, ASPRS, 2001.
McGlone, J.C., Mikhail, E.M. and Bethel, J., “Manual of Photogrammetry”, ASPRS., 2004.
Mora, O., Mallorquí, J.J., Duro, J. and Broquetas, A., “Long-term subsidence monitoring of urban areas using differential interferometric SAR techniques”, Geoscience and Remote Sensing Symposium, IGARSS '01, 2001.
Wolf, P., Dewitt, B., “Elements of Photogrammetry with Applications in GIS”, 2000.