关中平原城市群城市联系与影响范围分析

Connection and Influence Scope of Guanzhong Plain Urban Group

利用NPP-VIIRS夜间灯光数据,通过OD成本分析计算最短通行时间,对关中平原城市群2017年78个县级行政单元的规模、联系与影响范围进行分析。结果表明:关中平原城市群城市规模呈“金字塔型”结构,中小型城市发育,大城市数量少,具有空间集聚性;城市规模密度具有梯度特征,呈现出以西安为中心的单核心多层级空间分布形态;城市联系极化现象明显,具有普遍弱联系、个别强联系的特点;西安、咸阳、长安区形成强联系三角形城市带,但与大部分城市联系较弱,空间位置集中导致辐射范围重叠,限制了三者对城市群的辐射作用;城市联系强度表现出空间性、行政级别特征与交通依赖性;城市群影响范围呈现出“一超、两极、多强”的引力中心格局,据此,可将城市群划分为东、中、西南、西北四大城市影响区。

The urban scale and shortest traffic time calculated by NPP-VIIRS data and OD cost matrix analysis,and the gravitational models of cities,weighted voronoi diagram are used to analysis the scale,connection and affective range of 78 counties in Guanzhong Plain Urban Group in 2017. The research shows that the scale of urban group presents a structure of pyramid,the middle and small cities are multiple but the metropolis is least. what’s more,the metropolis have spatial aggomeration characteristics;The density of urban scale presents evident gradient variation and a morphology of single core with multiple hierarchies spatial distribution;the connections in the urban group is polarity,the weak connection is general but the strong connection is less. Xi’an Xianyang and Chang’an formed a triangle urban belt,but the weak connection with other cities and the concentrated position restrict their power to other cities;the urban connection is effected by the space location,urban administrative level and traffic;the attracting centre of-influence scope of urban group presents one superpower,two poles and many powers,so the influence regions of urban group can be divided into east,middle,southwest and northwest four parts.