A study on spatial accessibility based on urban metro traffic: A case study of Xinjiekou in Nanjing

In the last 30 years, because of continuous high economic growth, industrialization and urbanization, China´s urban form and spatial structure has undergone enormous changes. Besides, urban problems keep emerging, especially urban traffic congestion has become a hard-to-solve problem of major cities, which is severely restricting urban sustainable development. Facing the fast-changing of urban space and rapidly emerging urban problems, there is an urgent need of development of methods for traffic research. However, due to the lack of analytical tools, the existing theories and research methods are not enough to solve practical problems. Rapid development of GIS technology provides a powerful mean to solve complex spatial urban and regional issues. By study of common accessibility measurements and distance calculation methods, this paper constructs a improved-raster distance calculation model to overcome the weaknesses of simple network based vector methods and cost distance based raster methods when analyzing accessibility. This research use Nanjing as study area. With the rapid expansion of Nanjing, it become a typical city subject to urban traffic problems. This research uses the improved-raster distance calculation model to analyze the change of Xinjiekou spatial accessibility before and after the establish metro line 2.