Spatial field of the Yangtze River Delta Economic Zone:An application of regional accessibility and data field

Spatial field is an effective tool which can be used to describe the regional development pattern and spatial differences for the decision makers.With the application of principal components analysis,raster cost weighted distance method and k-order data fields,this paper attempts to comprehensively measure the nodality index for central cities,regional accessibility,as well as the spatial field in the Yangtze River Delta Economic Zone,and to reveal the spatial distribution and evolution of regional development.The results indicate that central cities in the Yangtze River Delta Economic Zone have made great progress during the past 10 years and this region tends to be evenly developed.Moreover,regional accessibility condition continues to be improved and the average accessible distance for 3 hours increased by 41 km(from 81 km in 2000 to 122 km in 2008).Most of the central cities in Yangtze River Delta Economic Zone have been covered in the 3-hour metropolitan area of Shanghai except for Zhoushan and Taizhou.In addition,regional spatial field increased significantly from 2000 to 2008.The spatial heterogeneities are conspicuous and the overall situation reveals that the spatial field in the north is better than that in the south.The distribution pattern of spatial field appears to be single-core with a Z-shaped pattern in 2000,while that in 2008 tends to be a multi-polar network form.According to the natural breaks method,the distribution pattern of spatial field in Yangtze River Delta Economic Zone can be appropriately divided into five major types,i.e.,higher field energy region,high field energy region,the transitional region,lower field energy region and low field energy region.Furthermore,the high field energy region is mainly located in the metropolitan areas of Shanghai,Nanjing,Hangzhou,Suzhou-Wuxi-Changzhou,and the development axis areas of Shanghai-Nanjing and Shanghai-Hangzhou.Most parts of the core and potential regions are located along the north wing of Yangtze River Delta Economic Zone.