Gene23
求助，看一个文献，文献内容是要计算一个分类预测的成功率（训练数据集），现在知道了文献作者怎么用模型计算出来LSI（滑坡易发性值），如LSI为：5.7~59.3（低易发性~高易发性）。接着需要计算这个易发性的正确率，也就是成功率success rate。用到的其中一个方法是ROC 曲线，这需要先将5.7~59.3 这样的易发性值划分为0（非滑坡）和1（滑坡）两类，所以要确定一个分割点，大于分割点分为滑坡1，小于分割点分为滑坡0。文章作者在确定分割点的时候写了这样一段话，看了很久还是不明白，在researchgate 上问作者也还没有回信，一直搞不明白作者究竟是怎么做的，求各位大神给点指点。
怎么确定分割点的原文如下：
The success rate was calculated as follows:
First, the LSI values were calculated from LSI maps in ascending power for the cumulative total and cumulative total in descending power.
Next, each calculated cumulative value was cross-applied to analyze the cross point. The cross point is the average point with the highest R-square for the LSI value.
The areas with values larger than the LSI value of the cross point were set to the areas with high landslide susceptibility (event: 1) and the areas with low landslide susceptibility (event: 0).
As a result, the LSI maps were classified into values of 0 and 1 according to the crossing point.
原文引用：Park S, Choi C, Kim B, et al. Landslide susceptibility mapping using frequency ratio, analytic hierarchy process, logistic regression, and artificial neural network methods at the Inje area, Korea[J]. Environmental earth sciences, 2013, 68(5): 1443-1464.
不明白的地方，首先作者说将计算出来的易发性值做升序累积和降序累计，接着做cross-applied【不懂什么意思】，然后不知道怎么就出来一个R square。
