珠三角公路通达性演化及其对城市潜力的影响

将空间句法模型与GIS结合,基于1990年、2009年公路网数据,定量分析1990年以来珠三角公路网通达性时空演变,进而探讨其对城市潜力变化的影响。结果表明：① 近20 a来,珠三角公路网拓扑连接等级差异趋于缩小、整体通达性显著提高,但核心区内部和外部路网发育差距趋于扩大;② 公路通达性总体上呈“核心-外围”结构,核心区范围不断扩大,至2009年以广-佛核心都市区、深-莞-惠都市区为最高,向外围逐渐递减,并形成了“∧”型高集成度轴线分布带及由此向外放射状延伸的态势;各等级公路轴线分布格局变化空间分异明显,公路网拓扑连接的区域不均衡性更加明显;三大地带公路通达性空间差异明显,中部最高且提高较快,东部次之但与中部差异趋于缩小,西部相对最低且与中、东部的差异进一步扩大;③ 公路网总体布局上智能性、可理解性有较大提高,但核心区外部公路智能度仍普遍较差;④ 公路通达性与城市潜力呈正相关性并得到增强,公路交通对城市潜力变化影响更加显著,但2009年仍属中度相关。

Road Network Accessibility and Its Influence on City Potential in Zhujiang River Delta

Based on the road network data of 1990 and 2009 in the Zhujiang River Delta (ZJRD), this article explores the spatio-temporal evolution of the road network accessibility and quantitatively analyzes its influences on urban potential change of ZJRD region with the support of space syntax model, GIS technology and statistical analysis method. The basic conclusions are obtained as follows: 1) The grade-layer difference of the topological connection of the road network has decreased, and the whole accessibility of the road network have been improved significantly from 1990 to 2009. However, the road network development gap between inner and out the core region of ZJRD has been enlarged. 2) The road network accessibility shows an obvious core-periphery structure as a whole, and the core area has been gradually expanded. In 2009, the road network accessibility of Guangzhou-Foshan metropolitan region and Shenzhen-Dongguan-Huizhou metropolitan region was the highest, gradually decreasing from those two regions to the surroundings, which results in the “∧-shaped” form of high integration axes and spatial pattern of the entire road axes stretching radially. There are obvious differences of the spatial distribution change of different grade road axes, and the imbalance of the topological connection of the road network is more significant. The road accessibility in the middle zone is the highest and has been improved quickly, and the east zone ranks the second highest and the disparity between the eastern zone and the middle zone has decreased. Whereas, the road accessibility in the western zone is the lowest, and the disparity between the western zone and the middle and eastern zones has been on a trend of expanding. 3) The spatial intelligibility of the layout of the road network as a whole has improved significantly, but most roads out the core region have still low spatial intelligibility and poor convenience. 4) There is a positive correlation between the road accessibility and city potential of ZJRD region, and the correlative degree has strengthened, indicating that the influence of road traffic on urban potential change is more significant. But it still remained a moderate correlation in 2009.