GEOGRAPHICAL RESEARCH ›› 2010, Vol. 29 ›› Issue (5): 863-872.doi: 10.11821/yj2010050010

• Geo-information Science • Previous Articles     Next Articles

Scale sensitivity and its causality for Geo-cellular Automata modelling

KE Xin-li1,2, DENG Xiang-zheng2,3, HE Shu-jin2   

  1. 1. School of Resources &|Environment Science, Xianning College, Xianning 437000, Hubei, China;
    2. Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China;
    3. Center for Chinese Agricultural Policy, CAS, Beijing 100101, China
  • Received:2009-10-26 Revised:2010-02-24 Online:2010-05-20 Published:2010-05-20

Abstract:

Geographical Cellular Automata (GeoCA) is an efficient model to simulate dynamic geographical process, which has been illustrated by a great number of researches. Surprisingly, there are few researches discussed in detail on the scale sensitivity of cell size during the geo-cellular automata modelling process. Among existing researches using GeoCA, cell size is always decided by the resolution of geographical data source. Whether cell size will affect the simulation results of GeoCA or not is a hotspot. If it does, what is the causality of scale sensitivity of GeoCA? How does cell size affect simulation result of GeoCA? And how can we choose a suitable cell size during geo-cellular automata modelling? Few researches have achieved answers for these questions. In order to figure out effects on simulation result of GeoCA caused by cell size and its mechanism, and to provide a principle to choose cell size for GeoCA, we take land use change simulation of Hangzhou City as a case, and choose cell sizes of 50m×50m, 100m×100m, 150m×150m and 200m×200m to analyze the scale sensitivity of GeoCA. And then, by analyzing transfer rule, causality of scale sensitivity is discussed in this paper. The research result shows that (1) simulation results of GeoCA are sensitive to cell size, and the more fine the cell sizes are, the higher the accuracy of the simulation results; (2) scale sensitivity of GeoCA is not uniform in all cellular sizes, it is sensitive in some range of cellular size while it is insensitive in other ranges; (3) scale sensitivity of GeoCA simulation results is by large caused by increasing isolated cells. These isolated cells and cells around them have lower neighborhood function value, and then their transfer probabilities are also lower. With the increase of cell sizes, the number of isolated cells in cellular automata space increases. Because of lower transfer probability of these isolated cells, these increasing isolated cells caused higher error rate of simulation results of GeoCA. So, the number of isolated cells is the main cause for scale sensitivity of cell sizes when we do the geo-cellular automata modelling.

Key words: Cellular Automata, geo-cellular automata, scale, scale sensitivity, land use, simulation