中小城市土地利用空间结构分析的尺度效应

SCALING EFFECT IN ANALYSIS OF URBAN LAND USE SPATIAL PATTERN IN THE SMALL URBAN

以内江市为例,采用土地利用信息图的方法、引入均质度的概念研究了城市土地利用空间结构,在Arc-Gis9.1软件技术支持下,选取5m×5m、10m×10m、15m×15m3种不同大小的网格系统,分析内江市城市用地的空间结构变化规律。研究表明:内江市城市土地利用的均质度在0.86以上,不同土地利用方式空间展布比较集中;3种不同大小的网格系统对土地利用均质度的影响有一定差异,在土地利用类型比较复杂,用地比较零碎的地方,网格尺度的变化对土地利用的均质度影响较大;而在土地利用类型单一,某种用地类型为主的区域,网格尺度的变化对土地利用的均质度影响较小。其原因是网格越大,越能掩盖零散分布的细小土地斑块,强化了区域内主要的土地利用类型;相反,随着网格的缩小,小地块的信息就可以逐渐提取出来,提取的土地利用信息变得复杂。

The urban land use spatial pattern in terms of land use evenness obtained from land use information map is studied.Taking Neijiang City as an example,based on the ArcGis9.1,the urban land use evenness was calculated by 5 m×5 m,10 m×10 m,15 m×15 m grid sizes in the land use information maps.The results showed that the evenness of Neijiang urban land use was above 0.86.Different land use patterns showed relatively centralized distribution.The evenness of 3 grid sizes land use was different.In the areas with more complex land use and more fragmented land,grid-scale changes greatly influenced the evenness of land use,while in the areas with a single land use representing a major area,the grid-scale changes showed samall effect for the evenness of land use.The reason was that the more grid-scale was,the more the distribution of small patches were covered up,thereupon,the region＇s main land use types were strengthened;on the contrary,with the narrow grid,small blocks of information could be gradually extracted,and the land use information extracted were more complicated.