Census Spatialization Based on Thiessen Polygons and Grids Smoothing:A Case Study in Xuzhou

First,the method of Thiessen polygons is employed to research on population density distribution in Xuzhou.Then,census of Xuzhou is spatialized by method of GCAWI.In order to smooth the results,we put forward a method of superimposed grids of different size,and population density distribution based on 500 m grid is drawn.The results show that: ① The population density is towards to move to south and extend to east of Xuzhou between the year of 2000 and 2005;② the method of superimposed grid of different size realizes census spatialization and smoothing;③ By comparising with population density distribution based on Kernel estimation,we can learn that the features in detail of population density distribution are refelected by using the methods of GCAWI and grids smoothing,however,only does integral pattern can be reflected by Kernel estimation.