A comparison of geographical information systems–based algorithms for computing the TOPMODEL topographic index
A comparison of geographical information systems–based algorithms for computing the TOPMODEL topographic index
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DOI：
10.1029/2004wr003069
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发表时间：
2004-06
影响因子：
5.4
通讯作者：
F. Pan;C. Peters-Lidard;M. Salé;A. King
中科院分区：
文献类型：
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作者：
F. Pan;C. Peters-Lidard;M. Salé;A. King
通过计算三种理想化山坡（平面、收敛和发散）的计算和理论地形指数的均方根误差，评估了六种基于地理信息系统（GIS）的地形指数算法的性能。除了这三种理想情况外，还有两种坡度不同的发散山坡，即，还测试了凹面（斜率从顶部到底部减小）和凸面（斜率从顶部到底部增大）。六种基于GIS的地形指数算法是流向和坡度算法的组合：即，单流向（SFD）、双向流向（BFD）和多流向（MFD）加上确定平坦区域中的斜率值的方法，例如，W-M方法[Wolock和McCabe，1995]和跟踪流向（TFD）方法。采用理想地形数据的水平分辨率和垂直分辨率的两种组合来评价这些方法。在这些算法中，MFD算法是最准确的，其次是BFD算法和SFD算法。随着垂直分辨率的增加，所有算法计算的地形指数的误差减小。我们发现，平面山坡的等高线的方向显着影响SFD的计算地形指数。如果等高线不平行于八个可能的流向之一，SFD的计算地形指数的误差是显着的。如果平均斜率较小，则TFD变得更准确，因为平坦区域的斜率值可以更好地估计。
The performance of six geographical information systems (GIS)‐based topographic index algorithms is evaluated by computing root‐mean‐square errors of the computed and the theoretical topographic indices of three idealized hillslopes: planar, convergent, and divergent. In addition to these three idealized cases, two divergent hillslopes with varying slopes, i.e., concave (slopes decrease from top to bottom) and convex (slopes increase from top to bottom) are also tested. The six GIS‐based topographic index algorithms are combinations of flow direction and slope algorithms: i.e., single flow direction (SFD), biflow direction (BFD), and multiple flow direction (MFD) plus methods that determine slope values in flat areas, e.g., W‐M method [Wolock and McCabe, 1995] and tracking flow direction (TFD) method. Two combinations of horizontal resolution and vertical resolution of the idealized terrain data are used to evaluate those methods. Among those algorithms the MFD algorithm is the most accurate followed by the BFD algorithm and the SFD algorithm. As the vertical resolution increases, the errors in the computed topographic index for all algorithms decrease. We found that the orientation of the contour lines of planar hillslopes significantly influences the SFD's computed topographic index. If the contour lines are not parallel to one of eight possible flow directions, the errors in the SFD's computed topographic index are significant. If mean slope is small, TFD becomes more accurate because slope values in flat areas are better estimated.