环境因子筛选及组合方法对滑坡易发性预测的影响规律
Influence of Environmental Factor Selection and Combination on Landslide Susceptibility Prediction Modeling
-
摘要: 采用不同筛选方法从滑坡环境因子中获取各种因子组合,将其作为滑坡易发性预测模型的输入变量,用以研究不同环境因子筛选及组合下的建模规律,对准确可靠地预测滑坡易发性具有重要的理论和实践参考价值.以三峡库区万州区为例,首先,选取23种环境因子,如地形、水文、岩性等;然后,用相关系数(Coefficient Analysis,CA)、线性回归(Linear Regression,LR)、主成分分析(Principal Component Analysis,PCA)、神经网络(Artificial Neural Network,ANN)和粗糙集(Rough Set,RS)等筛选方法来优化环境因子组合,将其作为支持向量机(Support Vector Machine,SVM)、多层感知器(Multi-layer perceptron,MLP)等典型机器学习模型的输入变量,构建CA-SVM、CA-MLP等耦合模型,预测滑坡易发性,并与未进行环境因子筛选的全部因子耦合机器学习模型作对比;最后,用受试者操作特征曲线下面积(Area under receiver operating characteristic curve,AUC)精度、易发性指数的均值和标准差等指标探讨建模规律.研究结果表明:(1)全部环境因子耦合的滑坡易发性预测精度总体上优于考虑环境因子筛选的机器学习模型,可见环境因子筛选对提升易发性预测精度并不理想;(2)滑坡易发性精度对不同环境因子筛选方法的敏感度略低于不同机器学习模型,显示开展环境因子筛选是不必要的,且其将导致建模过程更复杂,当然仍需避免采用相关性太高、且作用机制类似的环境因子.总之,可依据数据准确、类型齐全、意义明确、操作可行和主次清晰等原则,构建出完善的滑坡环境因子组合体系.Abstract: Different combinations of landslide environmental factors can be obtained under various selection methods,which are then used as input variables of landslide susceptibility prediction (LSP) models.Studying the modeling rules under different factors combinations can provide a theoretical and practical basis for more accurate LSP modelling.Taking Wanzhou District of the Three Gorges Reservoir Area as an example,23 environmental factors,such as topography,hydrology and lithology,are firstly selected.Then the correlation coefficient analysis (CA),linear regression (LR),principal component analysis (PCA),artificial neural network (ANN) and rough set (RS) selection methods are used to optimize the factor combinations.Next,the obtained factor combinations are used as input variables of support vector machine (SVM),Multi-layer perceptron (MLP) and other typical machine learning,to construct CA-SVM,CA-MLP and other coupled models.Meanwhile,these coupled models are compared with the All factors-machine learning models without considering environmental factors selection.Finally,the AUC accuracy,the mean value and standard deviation of predicted landslide susceptibility indexes are used to explore the modeling rules.Results show that :(1)landslide susceptibility predicted by All factors-machine learning is generally better than other models considering factors selection,indicating that factors selection is not ideal for improving the LSP performance;(2)The sensitivity of different factor selection methods to modeling performance is slightly lower than that of different machine learning models,suggesting that factors selection is unnecessary and may complicate the LSP modeling process.However,we still need to avoid using environmental factors with high correlation and similar mechanism to landslides.It can be concluded that,a satisfied selection and combination of landslide environmental factors can be constructed according to the principles of accurate data,rich types,clear significance,feasible operation and clear primary and secondary.