Topographic Variable Analysis And Lithology Classification Based On DEM

Lithologic identification and classification is the core content of regional geological surveys and mineral resources exploration.Rocks are aggregates of minerals and can form different topography by internal and external dynamic geologic processes.Topographic variables are derived from the Digital Elevation Model(DEM)and are quantitative indicators of the digital representation of topographic features.And topographic variable is a remote sensing geology.Visual interpretation and interpretation of core interpretation symbols in computer interpretation are crucial for the classification of lithology.And topographic variable is core interpretation symbol of visual interpretation about remote sensing geology,that is crucial for the classification of lithology.In this paper,three different landscape areas are selected from Guilin-Yangshuo Guangxi,Xingcheng and north of Xingcheng Liaoning,and Fuxili Daxinganling.Elevation,slope,curvature,and surface roughness etc.12 topographic variables are used to study the extent of correlation between lithology and topographic variables and how they are related,and how effective are the lithologic classifications of various topographical factors,and how effective the selected topographical variable combination scheme is for lithologic classification based on analysis of variance and cluster analysis.The research results are as follows:1.It analyzes the geological significance of topographical variables,and uses variance analysis and pedigree cluster analysis to quantitatively studied the correlation between lithology and topographic variable.It is confirmed that the same lithology has the smaller intraclass distance,different lithology has bigger the inter-class distances,that demonstrating a significant correlation between lithology and topographical variable,and the same lithologies have similar topographical features,different lithologies have different topographical features.2.It uses correlation coefficient to analyze the correlation of topographical variables,and uses the separability metrics in variance analysis to quantitatively evaluate the effectiveness of topographic variables to distinguish lithology.So we get that: the similarity of topographic variables grouping characteristics is mainly related to its geological significance.Topographic variables have different ability to discriminate different lithologies and the topographic variables with high correlation have similar distinguishing features.In the actual lithology classification,the topographic variables should be screened for optimal combination to fully exert the classification ability to improve Classification accuracy.3.Based on the geological significance of topographic variables and the separability metrics to construct the selection principle of topographic variables,and use the principle to select variables.It uses multivariate analysis classification method to classify lithology then uses the confusion matrix to evaluate the classification accuracy.So we get that: the classification accuracy based on selected variables is higher than the classification accuracy based on all variables.In the actual lithology classification,the classification accuracy and efficiency of lithology classification can be improved through the screening of topographic variables.