横断山区地表真实面积与垂直投影面积差异分析 ——以雅江县为例

横断山脉地形起伏复杂，以垂直投影面积作为地表真实面积进行定量计算会产生较大误差。本文以横断山脉中部雅江县为例，基于DEM数据和地表覆盖产品数据集，利用地表粗糙度的地学意义，计算了雅江县不同土地利用类型地表真实面积，并分析了地表真实面积与垂直投影面积之间的差异。结果表明：雅江县地表面积与投影面积的差异与DEM分辨率呈正相关，与海拔呈负相关；坡度是地表面积与投影面积差异的主要影响因素，坡度越大，差异越大，差异的增长速率越大；不同土地利用类型对面积差异有不同程度的影响。

Analysis of the difference between landscape surface area and vertical projection area in the Hengduan Mountains: a case study of Yajiang county

The topography of the Hengduan Mountains is complex. When vertical projection area is used to represent landscape surface area for quantitative calculations, large errors will occur. Taking Yajiang county in the middle of the Hengduan Mountains as an example, the landscape surface area of each land use type in Yajiang county is calculated by the geological significance of the surface roughness based on DEM data and surface cover product data sets. And the difference between landscape surface area and vertical projection area is analyzed. The results show that the differences between surface area and projected area in Yajiang county positively correlate with the DEM resolution, and negatively correlate with altitude. The main factor affecting the differences between the surface area and the projected area is the slope. As the slope increases, the differences and the growth rate of the differences also increase. The differences between surface area and projected area are diverse because of the different land use types.