地球表面之形貌變化,常因為地震引發地表破裂、颱風導致山崩與土石流、河川的侵蝕以及人為的開發所影響。花蓮地區地處花東縱谷的北端,在菲律賓海板塊及歐亞板塊相互作用下,因此地震特別頻繁;此外花蓮地區也位處颱風經常侵襲的路徑上故地表作用相對更為活耀。日治時期以來,人為開發的影響,使得花蓮地區地形地貌發生劇變。因此在分析花蓮地區之活動構造特徵、地形地貌之變遷等,歷史航照與日製地形測繪圖等早期影像資料,提供本世紀以來地形變遷研究不可或缺之資料,應用航空照片及立體像對可使用立體鏡判識地形特徵,並可建置數值地形模型;此外等高線地形圖提供平面座標與高程資訊,可以轉化成為三維空間資訊套疊於地理空間資訊系統中。因此本研究利用了日治時期台灣地形圖,如:台灣堡圖、台灣蕃地地形圖等,及美軍40-60年代間所拍攝之航空相片,並參考現今航空相片等不同時期、不同解析度之資料庫,試圖比對出長時間以來花蓮地區之地形變遷,並探討其改變的原因與對環境的影響。本研究成果指出從各時期數值地形模型與正射影像,可以分辨出許多人為開發所產生的地形變化如:北米崙台地上明顯地形階地、南濱公園等。歷史航照於立體製圖儀中清楚指出、並可以數化地形構造與河川侵蝕崖。運用各時期地形圖與正射影像,比對出花蓮海岸攤線逐年後退之速率。因此日治時期地形圖上有足夠的精度比對出本世紀以來海岸攤線差異,而航照精度足以辨識河道改變及區域活動構造之地形特徵。
Earth's surface morphology, due to earthquake caused surface rupture, typhoon caused landslides and debris flows, river erosion and the impact of human exploitation.Hualien is located in the northern end of the East Rift Valley, in the Philippine Sea plate and Eurasian plate interaction, so earthquakes are frequent; Also in the Hualien area are also located in the typhoon's path, so the surface effect is actively. Since the Japanese colonial period, the impact of human development, making the drastic change of terrain in the Hualien area. Therefore, the analysis of the Hualien area of active tectonic features, such as topography of the change, historical aerial photos and topographic mapping- Japanese images of early maps, topographical changes in this century to provide essential information research, Application of aerial photographs and stereoscopic machine can be used as find out topography, and can build digital terrain model; In addition, contour map to provide plane coordinates and elevation information, can be transformed into three-dimensional data in geospatial information systems. Therefore, this study used a topographic map of Taiwan during the Japanese occupation, such as: topographic maps were published in 1904 and 1916 . as well as the U.S. between 40-60 years of aerial photos are taken, reference to the current air photos of different times and in different resolution of the database, trying to compare a long time in the Hualien area of terrain changes, and to explore the causes of change and its impact on the environment. The research pointed out that the period from the digital terrain model and orthophoto, Can identify of human development arising from the changes in the terrain, such as: North Milun rock bench terrain is Clearly. Historical aerial photo in the stereo, can point out clearly , and digital of terrain strcture and river erosion. Use of the period and orthophoto topographic maps, Hualien coast than on the back of the coast line rate year after year. Therefore, topographic maps during the Japanese occupation sufficient precision than on the coast in this century coast line of difference, Aerial precision sufficient to identify the channel change and regional active tectonics of the topography.