數值高程模型解析度對嘉義沿海地區淹水模擬影響之研究－以賀伯颱風為例

Comparison of Maximum Simulated Inundated Depth of Herb Typhoon in Chia-I Coastal Region Using Different DEM Resolutions

楊昌儒(CHU-RU YANG) ； 蔡長泰(CHANG-TAI TSAI)

《台灣水利》 46卷1期 (1998/03) Pp. 43-52

摘要

暴雨期間之淹水範圍及淹水深度多需借助淹水模式演算。淹水模擬結果之正確性與地表高程資料之精確度密切相關，因此本文討論數值高程模型（digital elevation model-DEM）解析度對淹水模式分區代表高程之影響。將原始40×40公尺解析度數值高程模型分別以雙線性內插與選取最近點法重新取樣（resample），各產生20×20公尺與80×80公尺兩種解析度數值高程模型，比較重新取樣對分區代表高程計算之影響。並分析將此5組分區代表高程用於賀伯颱風淹水模擬所得之最大分區淹水深度之差異。由研究結果顯示當由原始40×40公尺解析度數值高程模型重新取樣時，均造成分區代表高程之差異，若將計算所得之分區代表高程用於賀伯颱風淹水模擬，將使淹水模擬結果之最大分區淹水深度產生顯著差異，其中又以雙線性内插方式重新取樣為80×80公尺解析度數值高程模型導致之差異最大。因此在淹水模擬上應審慎考量由不同資料重新取樣方式，產生不同解析度數值高程模型，對分區代表高程計算結果之影響，以增進淹水模擬結果之正確性。

關鍵字

數值高程模型 ； 地理資訊系統 ； 淹水模式

並列摘要

Owing to the use of distributed, physically based flood inundation models require analysts to acquire and utilize the spatial elevation data that are necessary. The digital elevation model (DEM) is ideally suited to storing and displaying these data. It can be used to analyze the structured or unstructured cell elevation values of the flood inundation models. So the resolution of digital elevation model is important for the precision and reliability of flood inundation model. This research use 40M × 40M resolution DEM for test, and two new DEMS with different resolution are created from the original DEM using the bilinear or nearest resample technique. The cell elevation values of the 5 DEMS are computed and compared. Then compare the maximum simulated inundated depths of Herb typhoon by using these cell elevation values calculated from different resolution DEMs. This test reveals the relationships among DEM resolution, cell elevation values and the maximum simulated cell inundated depths. These findings are valuable for the selection of the proper DEM resolution and resample technique for the flood inundation model.

並列關鍵字

Digital elevation model ； Geographic information systems ； Flood inundation model