Study On Spatial Form Evolution And Dynamic Simulation Of Changsha Urban

Cellular Automata (CA) is a kind of grid dynamic model which is discrete on time, space and state, with partial reciprocity in space and partial causality in time. The characteristics of CA , such as "from bottom to top" study method, powerful and complex calculation function, inherent parallel computing capacity, high dynamics and spatial concept, make it capable of simulating the spatial-time changes of complex spatial system, which thoroughly shows the soul of complex science, i.e. Complex structure comes from the interaction of simple subsystems. CA is adaptable for the simulation of complex spatial-time geography system and it has become an important tool and a research hot on the simulation of urban spatial-changes.The main contents and the conclusions of the thesis are as follows:(1) Analysis on the historic evolution of urban spatial form of Changsha and influencing factorsThe historic evolution of spatial form of Changsha was systemically reviewed and concluded. Then modern city spatial form evolution influencing factors of Changsha were deeply researched with study method of combination of the quantitative analysis and the qualitative analysis, the macroscopic analysis and the microscopic analysis.(2) Urban Planning Cellular Automata model (UPCA)Urban Planning Cellular Automata model (UPCA) from bottom to top and from up to bottom mixed was built up based on the SLEUTH model, by introducing the urban planning theory and method into CA model. There are mainly four aspects of improvement and they are improvements in cell spatial division, movement rules, data input layer and model function expansion. Finally, UPCA system software was designed and developed with geographic information system (GIS) technology.(3) Analysis on UPCA model spatial sensitivityAgainst the situation that most urban CA model with no consideration of the spatial scale of data input, taking Changsha as the example, it analyzed the UPCA model spatial sensitivity, drew that the appropriate resolution and the neighborhood structure of Changsha area are respectively 30m and C-1 (taking a cell as radius circular neighborhood). Furthermore, the best verification parameter upon these spatial criterions was gained.(4) Dynamic simulation of Changsha city spatial form and reasonable pattern constructionWith UPCA model, historic and future spatial form evolution process of Changsha was dynamically simulated. Then it calculated the simulation results and real situation based on fractal with GIS technology, and revealed current problems and trend of development, Moreover, the state of future city spatial form was simulated by setting different scenarios. It turned out that the spatial form under the plan scenario 3 (aiming at ecological environment protection, to occupy the least farmland, forest land and garden plot, considering the influence of various factors upon city development) was most reasonable for future urban spatial form of Changsha.Innovations and main contributions are that the thesis has:(1) Induced and analyzed Changsha spatial form evolution process and the factors;(2) Constructed the UPCA model based on the CA principle and the urban planning theory;(3) Hunted and analyzed the UPCA model spatial sensitivity;(4) Through the scenario simulation, sought the future city spatial form reasonable pattern of Changsha.It should be pointed out that the UPCA model is still at the stage of theory discussion. As the simulation on the complex system, urban spatial form is demanding on function mechanism of model, neighborhood structure, calibration method and time intervals are to be expanded, which will lead to a more precise simulation of urban spatial form evolution process.