Research on karst landform classification based on positive and negative terrains——Taking the karst region of Guizhou Province as an example
Topographic factors are intuitive and visual,and are often used as the main basis for karst landform classification.The topographic factors used in existing studies on karst landform classification are numerous and complex,and the classification features are not easy for public's learning and under-standing,which makes the application and promotion of the results difficult.The study takes the karst region of Guizhou Province as the study area,selects the important positive and negative terrain indica-tors and explores the classification method of karst landform based on the terrain openness method and random forest algorithm.The results show that:1)In the karst region of Guizhou Province,the aver-age nibbling degree is 1.35,while the average cutting depth is 215.36 m and the average mean-rough-ness-ratio is 1.01,the area of negative terrain is larger than the area of positive terrain,the positive and negative terrains are irregular and fragmented,and the positive terrain is cut by gully and valley obviously,and the heterogeneity of landform is strong.2)The importance indices of the two indica-tors,nibbling degree and cutting depth,are 0.93 and 1.16 respectively,which can better reflect the heterogeneity of karst landform.3)According to the two indicators of nibbling degree and cutting depth,the landform of karst region of Guizhou Province can be classified into 23 categories,with an accuracy of 93.33％.In different karst landforms,due to different levels of nibble degree and cutting depth,the abundance of soil,water,light and heat resources varies,resulting in different land use methods.Through this study,the terrain indicators used to classify and discriminate karst landforms are simplified,which reduces the difficulty of the public s learning and understanding on karst land-forms,and provides a reference for the popularisation and application of the digital terrain technology in the classification of karst landforms.
positive and negative terrainskarst landforms classificationnibble degreecutting depthrandom forest algorithm
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