多边形地形要素的向量计算方法

摘要

For the aspect calculation of the polygonal terrain elements,the arithmetical average method and the mode method are often used.These methods may cause an inversion problem of the polygonal raster data.Compared with traditional method,this paper presents a novel method which is vector algebra calculation method.In this method,the aspect of all the grid cells included in the map spot is regarded as a vector,and the comprehensive aspect of the map spot is equal to the algebraic sum of these vectors;through mode filtering,smoothing and other processing,the results are more consistent with the practical application needs and geographical description and understanding of aspect index.Compared with traditional method,the proposed method is simpler,more precise,and avoiding the aspect error.%对于多边形地理要素的坡向计算,多采用算数平均法及众数法,这种方法对于多边形栅格数据的计算,会造成南北倒置的问题.通过对传统方法的比较,提出了一种平均坡向的向量代数矢量计算方法跏,即将图斑所包含的所有栅格单元的坡向看成为向量,图斑的综合坡向就等于这些向量的代数和,并通过众数滤波、平滑等处理,其计算出的结果更符合实际应用需求,符合人们对坡向指标的地学描述和理解.与传统的使用栅格点算术平均值表达坡向的方法相比,该算法误差小,可克服坡向算术平均值所导致的坡向错误.