利用自製紅色地圖輔助地形判釋：以太魯閣地區為例

Interpretation of Terrain Features by Self-Developed Red Relief Image Map: A Case Study in Taroko Area

本文利用自行發展之紅色地圖技術輔助判釋台灣太魯閣地區之地形特徵。本研究紅色地圖成果乃結合地形開闊度與地形坡度而得到。用於產製紅色地圖之軟體為Generic Mapping Tools（GMT），而用於計算地形開闊度與坡度之數值高程模型為40公尺空間解析度。本研究主要目的為發展新的視覺化方法來表達地形特徵，以提供相關使用者細微且重要地形資訊，並希望後續能對災害預防、水土保持、環境監測與資源探勘做出貢獻。研究中依據不同地形開闊度計算之罩窗半徑值（200m~1600m），分為8個研究測試例。結果顯示，罩窗半徑1000m與1200m為最佳選擇。研究中發現，自製之紅色地圖與傳統等高線圖或分層設色圖相比，更能夠清楚凸顯出山脊線、山谷線與集水分區等地形特徵。 We develop the red relief image maps (RRIMs) to help interpretations of terrain features in Taroko area, Taiwan. The RRIM is produced based on the combination of the terrain openness and the terrain slope. The software for generating RRIM is Generic Mapping Tools (GMT). A digital elevation model (DEM) with a spatial resolution of 40m is used for both terrain openness and terrain slope computations. The purpose of this research is to develop a new visualization method of topographic maps in order to provide users subtle and important terrain information, and further bring contributions to the regions of disaster prevention, soil and water conservation, environmental monitoring, and resource exploration. In this study, 8 test cases for deriving self-developed RRIMs are designed according to the use of the different search radii for terrain openness computations. The result shows that the cases with search radii of 1000m and 1200m are best recommended. In addition, the ridgelines, valley lines and terrain-based subcatchments are more clearly revealed by the self-developed RRIMs than by the traditional contour plots and color mapping.

We develop the red relief image maps (RRIMs) to help interpretations of terrain features in Taroko area, Taiwan. The RRIM is produced based on the combination of the terrain openness and the terrain slope. The software for generating RRIM is Generic Mapping Tools (GMT). A digital elevation model (DEM) with a spatial resolution of 40m is used for both terrain openness and terrain slope computations. The purpose of this research is to develop a new visualization method of topographic maps in order to provide users subtle and important terrain information, and further bring contributions to the regions of disaster prevention, soil and water conservation, environmental monitoring, and resource exploration. In this study, 8 test cases for deriving self-developed RRIMs are designed according to the use of the different search radii for terrain openness computations. The result shows that the cases with search radii of 1000m and 1200m are best recommended. In addition, the ridgelines, valley lines and terrain-based subcatchments are more clearly revealed by the self-developed RRIMs than by the traditional contour plots and color mapping.