Study On 3D Forest Fire Spreading Simulation System Based On FARSITE

Forest fire can burst out suddenly, bringing destructive damage to various forest biologies and harm to ecosystem, what’s more, the difficulty of putting off the fire requires tremendous resources, posing a great loss to the nation and human’s life and properties. Currently, forest fire fighting policy is made mainly on the basis of monitoring data collected by remote sensing and lookouts etc. and with the assistance of two-dimension geographic information system (GIS). Information obtained by this method is relatively primitive and limited. By combining virtual reality and GIS technology with comparatively mature FARSITE two-dimension forest fire spreading simulation system, the spreading process of forest fire can be simulated in a 3D virtual forest environment. Meanwhile, this visualized and dynamic manifestation of forest fire spreading can effectively enhance peoples’understanding of the process and prediction, thus improving policy efficiency and accuracy and reducing the losses. This paper covers the following contents:(1) Domestic and overseas research progresses on mathematic model and computer simulation are summarized and reviewed. Advantages and disadvantages of different spreading models and simulating methods are compared and analyzed. The chosen spreading model and simulating method in this paper is thus confirmed as follows:3D visualization simulation is realized by integrating FARSITE spreading simulation engine and utilizing virtual reality and GIS technology.(2) By referring to forest fire burning mechanism and spreading principle, influence factors on forest fire are analyzed and various spreading models and simulating methods are compared. In-depth study is conducted on Rothermel spreading model and simulating method based on Huygens principle adopted by FARSITE simulation system. In addition to the introduction of data processing and simulating process of FARSITE system, the disadvantages of the system acting as a forest fire spreading engine are also discussed.(3) 3D terrain visualization technology and the organization mode as well as rendering principle in OSG are studied. DEM and satellite remote sensing images are processed to create a vivid 3D terrain of the studied region with OSG tool VPB and relevant GIS system. The principle and implementation method of particle system are studied, and 3D visualization of forest fire is realized by using particle system of OSG. A large-scale forest scene is established and it interacts with forest fire spreading simulation process by simulating the trees with Billboard technology and using the terrain as basic platform. The burning and spreading process of forest fire is dynamically simulated through a dynamic combination of 3D virtual forest environment and forest fire spreading engine module.(4) This paper also discusses generation principle of grid wind and its impact on forest fire spreading, which is visually displayed on 3D terrain, in an attempt to improve precision of forest fire spreading simulation and to visually show the influence of terrain on wind speed and wind direction.(5) A 3D forest fire spreading simulation system is established by demand analysis, system design and module division etc. on the basis of the aforementioned studies. Forest fire spreading process is dynamically simulated with the system and with the data such as DEM and forest map of the studied region. Besides, the simulation result is analyzed and summarized.