计算机图形技术在林火蔓延模拟计算中的应用

蔓延模型在过火区图元集和蔓延灰度图的基础上进行位图操作和轮廓搜索,用蔓延填充处理地理要素的复杂拓扑关系,以位图旋转和错切代替过火区形状的投影变换,利用地形灰度图计算太阳辐射,由此克服了原有波动模型计算性能上的局限.对利用图形技术提高计算速度的实质作了理论分析.最后用算例证实了文中模型能提供精确、实时、可靠、全局、易维护、高适应性的火场发展图.

Application of Computer Graphic Techniques in the Simulation for Forest Fire

In the new spread model for forest fire, bitmaps are operated and outlines of images are searched at the basis of the metagraphic set of fire-area shapes and the gray level image for spread calculation. Complex topological relations among geographical elements are solved with the scan-line floodfill algorithms. The projection transition of the fire-area shape is replaced by a combined graphical transformation of rotation and shear. And the solar radiations are calculated by means of the gray level image of terrains. Thus the limitation on computational performances of the original wave propagation spread model is overcome. The essence of computational acceleration making use of computer graphic techniques is analyzed primarily. A calculation case is presented in order to show that the new spread model can provide forest fire management with precise, reliable, overall, maintainable and adaptable diagram of fire development in real time.