國土變遷可分為自然與人為兩方面：自然方面，如海岸線變動、崩塌、土石流及淹水等情形；人為方面，如山坡地違規、違建、濫墾、傾倒廢棄物等。對於地表變動監測，衛星遙測的優勢，不受地表高度限制，且可快速與準確地進行資料處理，對於國土變遷普查，是一個非常有效的工具。其中崩塌與違規濫墾是臺灣地區較常見的山區變動，崩塌是災害，幾乎每年都會伴隨颱風或豪雨發生，違規濫墾造成土石外露是崩塌與土石流素材的來源之一。農委會水土保持局自 1995年起，即利用遙測科技進行山坡地管理與監測，結合遙測影像與 GIS判釋系統，進行山坡地變異監測及地形變動分析，除了每年皆查獲違法點位之外，間接對想取巧之徒也有嚇阻效果，並減少現場查報人員的人情麻煩。地形變動分析可以對崩塌地判釋、統計分析、與圖資建置，提供最新資訊，做為治災防災之參考。

Land surface changes are generally due to natural or human forces. For example, coastal changes, landslide, mudslide, and floods are all triggered by natural forces. While over-developed and illegally waste dumping in slopeland are owing to man-made impacts. Remote sensing as a powerful tool for change detection of wide area land surface can supply fast and accurate processing and analysis. This paper gives an overview about applications of satellite image, including change monitoring of slopeland, landslide analysis, acquiring of surface deformation, and change detection of waterline in west Taiwan. Application of remote science and technology in management and monitoring, including slopeland monitoring and landslide analysis, has been proceeding since 1995 by Water and Soil Conservation Bureau of the Council of Agriculture. These works are all the resources of government’s administration in precaution against natural calamities.