基于多阶邻接度指数的城市景观扩张格局演变分析——以昆明市呈贡区为例

Analysis of the Evolution of Urban Landscape Expansion Pattern Based on Multi-Order Adjacency Index:A Case Study of Chenggong District,Kunming City

城市景观既是城市扩张的典型特征,又是评判城市化水平的重要指标。度量城市景观扩张特征并分析其时空演化格局有助于人们了解城市发展的态势,进而为城市合理规划提供依据。以云南省昆明市呈贡区为例,基于多阶邻接度指数(Multi-order Adjacency Index,MAI)和空间自相关分析方法测度并分析了该区域2005—2020年(每5年为1个计算周期,共3个时段)的城市景观扩张特征及其时空格局演化态势。首先,运用MAI值度量了研究区的城市景观扩张特征;然后,基于MAI值,运用空间自相关分析方法探测了城市扩张的空间聚集特征与趋势。结果表明:1)蔓延式和边缘式是研究区主要的城市景观扩张类型,其他类型较为平均且与上述两种类型比较有明显差距;2)城市发展早期(前10年),蔓延式占绝对优势,后期这种趋势明显下降;3)MAI值的高-高聚集区域呈现由中间向四周扩散的趋势,城市化步伐正朝“紧凑”方向发展。上述结果表明:结合MAI和空间自相关是度量和探测城市景观扩张特征及其时空演化过程的有效途径。

Urban landscape is not only a typical characteristic of urban expansion,but also an important indicator to evaluate the level of urbanization.Measuring landscape characteristic and analyzing its spatio-temporal evolution pattern is helpful to reveal the trend of urban expansion and provide a support for rational urban planning.Taking Chenggong district of Kunming of Yunnan province of China as the case study,this issue measured the characteristics of urban landscape expansion with Multi-order Adjacency Index(MAI)and analyzed its geographic cluster pattern using spatial autocorrelation analysis method from 2005 to 2020(every 5 years is a calculation period,and there are three periods in total).Firstly,we measured the characteristic of urban landscape according to the MAI values,and then,based on the MAI value,the spatial autocorrelation analysis method was adopted to detect the geographic cluster patterns and the urbanization trend.The results showed that:1)Sprawl type and edge type were the main types of urban landscape expansion in the study area,while the other types were more average and have obvious gap compared with the above two types;2)In the early stage of urban development(the first 10 years),the sprawl type dominated,and then the trend was obviously declining in the later stage;3)The high-high cluster areas of MAI showed the trend of urban expansion from the center to the surrounding areas,and the pace of urbanization was developing towards the direction of“compact”.These results indicated that the combination of MAI and spatial autocorrelation is an effective way to measure and detect the characteristics of urban landscape expansion and its spatio-temporal evolution process.