The characteristics and patterns of spatially aggregated elements in urban areas of Wuhan
JIAO Limin;LI Zehui;XU Gang;ZHANG Boen;DONG Ting;GU Yanyan;School of Resource and Environmental Sciences,Wuhan University;Key Laboratory of Geographic Information System,Ministry of Education,Wuhan University;State Key Laboratory of Information Engineering in Surveying Mapping and Remote Sensing,Wuhan University;
Different urban elements may exhibit various aggregation patterns.It is of great significance to quantitatively investigate the disparity and connection among various aggregation patterns of urban elements for understanding the mechanism of urban development and supporting urban planning.Taking Wuhan city,Central China,as a case,we collected five types of urban elements,namely,impervious surface,population density,Point of Interest(POI),plot ratio,and road network,to explore their spatial distribution and characteristics of aggregation patterns.We first used Kernel Density Estimation(KDE) method to identify city centers and we found that there is one major center and seven sub-centers in Wuhan.Then we partitioned the study area by gradient analysis,and calculated the densities of urban elements.The density of urban element decreases outward from the centers,which is fitted well using "Inverse S-shaped" function.We used Concentration Degree Index(CDI) to reflect the aggregation degree of urban elements.The results indicate that the degrees of the aggregation of urban elements are:Commercial POI population plot ratio road.Commercial POI and population are highly aggregated in the urban core area,while plot ratio and road are moderately aggregated in the urban core area.The spatial patterns of highly aggregated commercial POI and population are the combination of point pattern and zonal pattern,while the spatial patterns of moderately aggregated road network and plot ratio are the combination of point pattern,ring pattern and axial pattern.As for the lowly aggregated impervious surface,it shows a ring pattern.The attraction effect of city centers and vertical development promote the center-oriented agglomeration of urban elements.At the same time,the transportation lines and corridor effects of the scarce landscape resources reshape the spatial distribution pattern of urban elements.
【Key Words】： urban elements spatial agglomeration kernel density estimation gradient analysis inverse S-shaped function Wuhan city
【CateGory Index】： F127
【CateGory Index】： F127