Extraction of landform information in Changbai Mountains based on Srtm-DEM and TM data

Basic landform are the most fundamental geomorphologcal units that only inferior to Plain and Mountain. Which controls the distribution and change of other ecological and environmental factors to some extent and plays an important role in extracting more detailed landform information in the whole geomorphological system. In this article, based on the project "1:1,000,000 digital geomorphologic mapping in China". A semi-automatic method was designed to extract the basic landform types from Srtm-DEM and TM imagery and which was demonstrated with a case study of the Changbai Mountain in Jilin Province. Firstly, The primary plain and mountain were automatically extracted from Srtm-DEM by intergrating Borough\´s slope model with Natural Breaks and Manual slope classification. Secondly, the sketch map of the basic landform types was obtained through overlaying the altitude and relief value. Thirdly, the more precise basic landform types boundaries were obtained and manually interpreted based on previously obtained plain and mountain boundary and expert\´s interpretation of TM imageries who takes into account the relationship between landform and other geographical phenomena, such as geology, vegetation, landuse, and soil. Therefore, the method of semi-automatic extraction of landform information based on Srtm-DEM and TM imagery was primarily realized. Compared to historic 1:500,000 geomophological maps, the results show that the overall kappa coefficient of accurate assessment was more than 80%, which is satisfied. In addition, the method introduced in this article has the advantages to other methods: it can improve the work efficiency and reduce the workload of the researchers, and the forms of the results are digital and can be updated on time.