Study On Typical Geomorphological Feature Extraction Based On Multi-source Data

This paper summarizes the progress of geomorphology research and the geomorphological information extraction methods at home and abroad and takes the typical geomorphological feature extraction as its main study contents.This paper introduces the parameters which are used most in the process of automatic / semi-automatic extracting geomorphological features.The parameters include elevation,slope,profile,relief,cutting depth of the surface and etc.Then the paper sums up three methods for extracting geomorphological features:1) Using the combination of geometry and topography for extraction;2) Expert-driven object-oriented geomorphological features extracting;3) Combining the remote sensing and elevation data for extraction.Additionally,the paper takes the extraction of craters in Jingyu County,Jilin province and the extraction of geomorphological features in section of the Songhua River in Harbin as an example.In the process of extracting craters,according to the characteristics of the study area that the craters are located on the lava platform,the study area is divided into plain and mountain.Then,the slope data is multiplied by the elevation data,which is similar to weight the elevation in accordance with the relief.It is a way to better highlight the craters in the elevation data on the performance.Take into account of the craters' form characteristics- intermediate low,around high-and their performance on the DEM,established a template for craters identification.Finally,the results of the extraction need verification and revision based the remote sensing image.In this paper,the expert-driven object-oriented method is used for terraces extraction.Firstly,the image in the study is classified into water body and land(not water body).And then in accordance with the relationships among geographical features,the delta,low floodplain,high floodplain,terrace and plain are extracted. Terraces and plains in the remote sensing images showed high similarity,it is difficult to distinguish,for further differentiate,it is necessary to use the DEM data for classifying plains and terraces.When the form feature extraction finished,the next step is classifying the polygons according their largest elevation,according to geological data discriminating the polygons' main causes,secondary causes and.the material composition.Eventually,the geomorphological data for geomorphological are formed.When extracting geomorphological features form DEM and remote sensing data, first of all,the study area should be understood deeply.Then sum up the extracting targets' performance on DEM and remote sensing data,choosing the best portrait of geomorphic indicators to extract patterns.At the same time,the process of extraction also should make full use of space entities the law of spatial distribution and composition of the law for the classification.In addition,the final results of the extraction not only should be smoothed and generalized,but also be modified in accordance with the views of experts who know well of the study area.