Study On Relationship Etween Comprehensive Terrain Complexity And Appropriate Resolution Of Grid Based On DEM

The temporal and spatial distribution of geographical objects is often expressed on a scale-dependent basis.But due to limited data storage space and time efficiency,choosing a appropriate scale is especially important to reveal the objective law of temporal and spatial distribution of geography objects.Therefore,the choice of appropriate scale has been a hot topic in geography and related disciplines researches,and also one of the important access to solving the problem so-called "scale gap".At present,the appropriate scale research in DEM terrain analysis is fruitful.Researchers usually use the DEM itself or terrain information derived from DEM to characterize the scale effect and select the appropriate scale.However,different methods use different quantitative indicators,which leads to the result that the choice of appropriate scale is not applicable and lack of quantitative evaluation of effectiveness.For the above circumstances,based on the comprehensive terrain complexity,this paper attempts to construct a model of rationable and scientific DEM comprehensive terrain complexity and grid proper resolution by statistical regression method.This paper chooses the complex areas of western Yunnan as examples,and aims to discuss how to select and apply the appropriate scale to display spatial analysis in the areas where the terrain conditions are more complicated and the landforms are diverse.The results indicated that:(1)The terrain features such as the slope variability(SOS),the aspect variability(SOA),the plan curvature and the profile curvature can effectively express the terrain complexity.The results show that the terrain features expressed by the above four basic topographic factors have scale correlation.(2)The integrated terrain complexity index obtained by the weighted quantization of the basic terrain factor has the fractal characteristics,and the minimum spatial resolution of the study area can reflect the maximum spatial resolution of 150m by the fractal box dimension.The resolution can guarantee the accuracy requirement,but also to ensure the highest efficiency of time.(3)The calculation model of grid DEM suitable resolution based on comprehensive terrain complexity is basically consistent with exponential function trend.In the case of 95%confidence,the degree of fit can be as high as 0.9482.The model can be applied to the study of variable resolution DEM with spatial variability.It provides the basis for dynamic selection of suitable resolution in digital terrain analysis and the rationable and scientific calculation model and method.This study could lay the foundation for exploring universality of the models of select appropriate resolution.