这 Publication Issue 用你的语言不存在, 用...查看: English (en),
或使用谷歌翻译:  

The humid landscape is water controlled, and unless it is an extremely new landscape- volcanic or newly faulted--it has softly rounded outlines. When you are walking up the valley, or walking on the ridge, observe that there is a rounded 'S' shaped profile to the hills.

Where the landscape turns from convex to concave occurs a critical point that we call a keypoint.*


Articles