长江上游地区经济腹地农村道路体系的优化与网络分析

Optimization of the Rural Road System in the Economic Hinterland of the Upper Reaches of the Yangtze River and Its Network Analysis

在四川省、贵州省和重庆市选取了5个样区,参考各样区农村道路建设标准,优化富有长江上游经济腹地区域特色农村道路体系.借助ArcGIS9.3的空间统计分析功能和网络分析法,分析道路网络空间特征指数,揭示了区域道路体系及其网络特征的差异性和规律性.结果表明,长江上游经济腹地5个样区自然环境、社会经济等差异加剧了各级道路体系优化重点的区域差异:桐梓样区(贵州省)和秀山样区(重庆市)在优化路网的同时重在提高路面质量,芦山样区(四川省)、合川样区和忠县样区(重庆市)重在优化环路网;各样区的网络特征指数除成本比C指数有所降低外,其余均有不同程度提高;农村道路网络空间特征存在一定的规律性:道路密度与网络闭合度α指数、线点率β指数、网络连接度γ指数呈正相关关系,而与C指数呈显著负相关;Moran指数进一步表明:通过道路工程优化,地势相对陡峭的样区道路密度显著增加,而地势相对较平坦的样区道路密度增幅不大.因此,农村道路作为一个农村景观廊道或农田物质流、价值流通道,可用网络分析进行评价,并实现农村道路体系网络优化.

Choosing five representative sample areas in Sichuan, Guizhou and Chongqing, this paper opti mized the rural road system befitting the upper reaches of the Yangtze River, referring to their regional Standards of Rural Road Construction. Then the characteristic indexes of road network were discussed by ArcGIS9.3 and network analysis to reveal the difference and regularity of the regional road systems and their network characteristics. The results showed that the difference in the key link in road system optimization at each level was intensified due to the discrepancy of natural environment and social and economic development in the five sample areas, attention of road construction was focused on improving the quality of road surface and optimizing road network in Tongzi （Guizhou） and Xiushan （Chongqing）, while the main concern was given to forming a circular road network in Lushan （Sichuan）, Hechuan and Zhong County （Chongqing）. Except index C （cost ratio）, which decreased slightly, the other network indexes improved, to different extents of the rural road network, roa d in all the 5 areas. Some regularities were revealed in spatial characteristics density was positively correlated with network closure index a, line-point rate index β and network connectivity γ index, and significantly negatively correlated with index C. Moran index further indicated that after engineering optimization of rural roads, road density increased obviously in sample areas of rugged terrain but not conspicuously in flat sample areas. Therefore, as a rural agricultural landscape corridor or channel for material flow and value flow, the rural roads could be evaluated by the network structure analysis, and the network optimization of rural road system could be attained.