邻域算法在景观分析中的应用

景观过渡带是景观空间异质性较高的地区,在分析中经常需要从中提取不同类型区的界线,确定相应的范围。提出一种基于邻域概念的简易算法,根据分界线两侧景观的显著差异,在非特定方向上对连续或者离散的景观单元进行类型判定,依据界线的位置特征和类型隶属上的双重属性设定临界值,在此基础上得到判定条件下的单元,消去孤立分布的单元后,经格式转换求出分界线。本文以首都圈景观为例,给出这种算法的明确步骤,解析出地貌分界线,检验了这种方法的准确程度,简要讨论这种方法的特点和适用性,并在其他景观分析中进行推广验证。这种算法能够确定两种复杂分布类型之间的界线,适用于划分农牧交错区,提取地貌分界线和谷缘线等分析。

Application of neighborhood processing in landscape analysis

A transitional zone in landscape has a character of high spatial heterogeneity, from which demarcation lines are usually needed to be drawn for delineating various categories of landscapes and their extents. According to distinct differences of landscapes on both sides of the demarcation lines, and using GRID in ARCGIS, this paper provides a simpler and easier method based on cell-by-cell neighborhood processing. First it divides all the cells alternatively into two classes by an attribute, and then deduces which category the processed continuous or dispersive cells should belong to at random directions. And it sets a critical value according to location characteristics of borderlines and double-handed attributes on classification. Then grids close to the demarcation line are selected by their short distance, because after neighboring processing, the closer grids have a higher attributive degree than the farther ones, and the discontinuous and lonely grids are abandoned so that the continuously distributed cells near the demarcation line can be got. After vectorization of grid layer, the line coverage can be used to select the demarcation line with the help of reference maps, such as hillshade or land use distribution maps. Taking the regions near the Capital, China, this paper gives definite mechanics of neighborhood processing, draws morphological boundaries out of landforms, checks accuracy of the method, and briefly discusses its meanings and availability. Also, it applies this method to other fields of landscape analysis for application and validation. The neighborhood processing can trace the borderline between two classes of landscapes which are distributed complicatedly on two-dimensional space, and can be used to search the demarcation lines of agropastoral transitional zone, geomorphological on the Loess Plateau, etc. demarcation line, or shoulder line of valleys