An implementation of hillslope delineation algorithm / 一种坡面单元划分实现

[crazyzlj]

增加了坡面划分代码

• 代码位于seims/preprocess/sd_hillslope.py

• 输入数据为河网栅格（河网值大于0），D8流向栅格

  • 对于河网栅格，如果不是经过序列编号（即1, 2, 3, 4...），则首先根据D8流向对大于0的非空栅格进行序列编号
  • 输入河网和流向应具有相同的行列号，否则程序退出

• 输出数据为编码后的坡面栅格

  • 编码规则（MaxStreamID为最大河网编码）：
  • Header hillslope: MaxStreamID * StreamID + 1
  • Right hillslope: MaxStreamID * StreamID + 2
  • Left hillslope: MaxStreamID * StreamID + 3
  • 为方便后续使用，根据河网栅格的赋值不同，程序共输出4个文件：
  • hillslope.tif - keep stream link code
  • hillslope_1.tif - Set to the value of right hillslope and head hillslope
  • hillslope_2.tif - Set to the value of left hillslope and head hillslope
  • hillslope_3.tif - Set stream cell to NoData

• 代码思路借鉴Whitebox GAT v3.4.0 --> HydroTools --> Hillslopes

• 请有兴趣的同学一起测试、完善

Latest update: 2017-7-21

[houzw]

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[crazyzlj]

Hillslope algorithm in Whitebox GAT may have a bug in handling the situation that converging points of two upstream are adjacent to the head stream cell of their downstream (e.g., Fig. 1). The result can be found in Fig. 2. Fig. 1 Example of stream link with the arrow indicates D8 flow direction

Fig.2 The hillslope result derived by Whitebox GAT 3.4.0.

After careful review, I have implemented a correct version integrated into the preprocessing script of SEIMS in Python. The result is shown in Fig. 3.

Fig. 3 The hillslope result derived by SEIMS.

I have started an issue at Whitebox GAT's Github page.