Study on Computing the Area of Mountain Regions in China Based on DEM

So far,the mountain regions of China are still no unified boundaries.Among the many influencing factors,the definition of mountain and the calculating scale of terrain relief are two of most important.Mountain is that many scientists are difficult to closely define the scientific object and academic terms;so far,there is no unified definition of the mountain.The authors summarized and analyzed the previous studies about mountain definition and mountain range,proposed four quantitative definitions of mountain:1)the elevation is over 2 500m,or slope is over 25°or terrain relief is over 50m when the elevation is between 500mto 2 500m,or terrain relief is over 50m when the elevation is lower 500m;2)the elevation is over 2 500m,or slope is over 25°or terrain relief is over 50m when the elevation is between 500mto 2 500m,or terrain relief is over 100m when the elevation is lower 500m;3)the elevation is over 2 500m,or slope is over 25°or terrain relief is over 100mwhen the elevation is between 500mto 2 500m,or terrain relief is over 50mwhen the elevation is lower 500m;4)the elevation is over2 500m,or slope is over 25°or terrain relief is over 100mwhen the elevation is between 500mto 2 500m,or terrain relief is over 100m when the elevation is lower 500m.Combining the calculating scale of terrain relief,the study droved four results of area of the mountain regions in China.Through comparison with the existing data,the study determined the definition for mountain in China,and finally acquired that the area of mountain region in China is 6 588 100km2,which accounts for 68.2%to the terrestrial land of China.By the scientific definition of the mountain range,the study provides a basis and support for the survey of ecologic environment resources and the humanities and the social economic.