Regional accessibility analysis for digital urban planning based on GIS

China has been going through urbanization, and foreign experiences show that urbanization would finally lead to integrated planning and development of region. In regional planning, traffic network is an important aspect, which affects the impact of cities. However, in traditional accessibility analysis, only traffic lines are taken into consideration, while the influence of stations is ignored. This lead to the actual problems that traffic facilities cannot play the roles designed in regional planning when they are really constructed. Therefore, firstly, two rank traffic networks system are proposed, and different traffic networks with the normalization costs are combined to analyse the accessibility of the cities. Secondly, a new accessibility analysis method to get arrival domain for a city is proposed, which take not only the traffic lines but the traffic stations into consideration. Finally, the Jing-Jin-Ji Region is taken as an instance to show the effect of the new method.