苏北地区的空间梯度分析

从经济联系强度的角度出发，运用城市中心性、经济联系总强度与隶属度模型，探讨苏北地区的空间范围．根据熵值法确定徐州为苏北的中心城市，以徐州为中心划分出核心圈层与外围圈层；根据经济联系强度、隶属度等对苏北地区28个县市进行了空间重构，初步将苏北地区划分为3大区域，并结合相关分形理论对其进行验证．结果表明，徐州城区、丰县、沛县、睢宁、新沂、邳州、宿迁城区、连云港城区、沭阳、东海、泗阳、泗洪、赣榆、灌云14县市构成了以徐州城区为中心的徐宿连区；淮安城区、灌南、涟水、盱眙、洪泽、金湖、响水7县市构成了以淮安城区为中心的淮安区；盐城城区、射阳、建湖、阜宁、东台、滨海、大丰7县市构成了以盐城城区为中心的盐城区．

Analysis on spatial gradient of the regions in Northern Jiangsu

From the perspective of economical relation intensity, the spatial scope of five regions in Northern Jiangsu is studied by using the models of urban centricity, total economic relation, and membership degree. According to the entropy method, we determine Xuzhou as the central city of Northern Jiangsu, and divide Northern Jiangsu into core layer and peripheral layer. Based on economical relation intensity and membership degree, the 28 counties of North- ern Jiangsu are reconstructed and divided into three regions preliminarily. The result has been tested and verified through fraetal theory. The analysis shows that Xuzhou City is the core of Xu-Su-Lian region, which includes Xuzhou City, Feng County, Pei County, Suining, Xinyi, Pizhou, Suqian City, Lianyungang City, Shuyang, Dong- hai, Siyang, Sihong, Ganyu and Guanyun; and Huai＇an City is the core of Huai＇an region, which include Huai＇an City, Guannan, Lianshui, Xuyi, Hongze, Jinhu, Xiangshui; and Yancheng City is the core of Yancheng region, which includes Yaneheng City, Sheyang, Jianhu, Fu＇ning, Dongtai, Binhai, Dafeng .