JIANGSU URBAN ACCESSIBILITY IN TERMS OF LAND TRANSPORT
利用ArcGIS和VB编程，通过网格分析法提取江苏省65个市县中心在1990、1996、2002和2008年的直线距离和可达性数据，分析可达性演变特征，发现城市间可达性显著提升，结构从纺锤型变为支付型，差距持续缩小。
The evaluations of accessibility generally include network analysis and raster analysis.With the spatial analysis function of ArcGIS and the VB programming language,by the method of grid analysis,to regard the 65 administrative center of counties or cities in Jiangsu Province as the nodes,under the help of traffic network data of Jiangsu Province in the year of 1990,1996,2002 and 2008,straight-line distance and accessibility data are extracted between each of the 65 cities in Jiangsu Province.Based on the accessibility data,the paper analyzed the accessibility of Jiangsu Province for four study years and discussed the evolution characteristics.The conclusions show: The accessibility between each of urban in Jiangsu Province is improved significantly,and the structure is evolved from spindle type to down payments type,the gap of accessibility continued to narrow,the urban contact each other more strongly.Natural conditions and regional conditions are the factors of the accessibility's improvement.Differences in the development of transport infrastructure,lead to the changes of urban accessibility and regional advantages.