广东省公路交通网络分形空间特征研究

基于分形理论,以GIS技术为支撑,利用回转半径法测算了广东省全域及其所辖21个地级市公路交通网络半径维数D_L、分枝维数D_b和对应相关系数R²。依据广东省公路交通网络的特点,将其辖区分为四个子区域:珠三角、东部沿海、西部沿海和粤北地区,分析其半径维数和分枝维数的空间分布特征。研究表明,珠三角地区为广东省公路交通网络密度最大、结构最复杂、功能最完善、连通性最优的区域;以珠三角为中心,广东省公路交通网络分形半径维数和分枝维数随距离增大而衰减,沿海衰减程度微弱,粤北衰减程度较大。结果显示,半径维数和分枝维数结合能够更为合理系统地分析交通网络分形特征的时空差异特性。

Fractal Theory Based Study on Highway Transportation Networks in Guangdong Province

In the early 1990s Frankhouser discovered the powerlaw relationship between the length L(r) of railway networks and the radius(r) of an area,and calculated the radial dimension value when he investigated the sub-railway in Stuttgart.Because of the scale-invariance in a statistical sense,fractal theory is a suited method for the distribution of highway transportation networks.Based on GIS technology,radial dimensions(DL),ramification dimensions(Db) and correlation coefficient(R2) of the distribution of highway transportation networks are measured and calculated in the 21 municipalities of Guangdong Province.According to the spatial pattern of highway transportation networks and the development characters of infrastructure,the province is zoned into four sub-areas(Pearl River Delta Area,East Coast Area,West Coast Area and Northern Guangdong Area) for analyzing the fractal characteristics of highway transportation networks.Pearl River Delta Area is the region with the biggest density,most complex structure,best connectivity and most mature function of transportation networks in the whole province.The fractal dimensions of highway transportation networks decay with distance from the Pearl River Delta Area to the fringe areas,while the decaying degree is lower in Coast Area and higher in North Guangdong Area.The fractal dimension value approximate 1.7 is likely a suitable indicator for the perfectness of transportation networks morphology,structure and function.The fractal dimension of Dongguan(1.6287) is greatly approaching the indicator;therefore,it can be determined that the transportation network is rather mature in this municipality.The results obtained show clearly,the combination of radial dimensions and ramification dimensions enables the comprehensive analysis of spatial pattern characteristics of density,structure,connectivity and function of transportation networks.