Application Research Based On The Theory Of Uniformity And 3d Virtual Forest

Forest is the main body of terrestrial ecosystem,with various types and complex structures.Vivid,complete and objective simulation of forest ecosystem,accurately and intuitively providing all kinds of forest information and achieving effective human-computer interaction will be helpful to scientifically and reasonably guide the production and management of the forestry,and promote the healthy and stable development of forest ecosystem.3D virtual forest is a new technology integrating topography,forest type map,forest resource survey data and other information.It can vividly and intuitively express the spatial information and attribute information of three-dimensional terrain,forest type map and individual forest.It has a broad application prospect in the forest resource management and optimization of the afforestation.This research takes the computer graphics,the theory of uniformity and other theories as technical support,and applies the object-oriented language VC++ and OpenGL as development platforms,and with the help of the two-dimensional data management means---MapObjects,compiles all the research results into a software---3D virtual forest system.The research results are as follows:(1)Test of spatial pattern of trees:Under the guidance of the uniformity theory,a new detection method is proposed,When any two points contained in a random pattern are adjacent to each other,the volume of the contained exclusive sphere is equal,that is,it is positively correlated;Otherwise,it is independent.When the number m in the included random pattern tends to infinity,the variance of the included uniformity tends to 0,and the included uniformity converges according to probability.In this research,starting with the relevance,the correlation coefficient of the volume of the contained exclusive sphere is estimated and the convergence of the contained uniformity is proved.Furthermore,the convergence of the uniformity is used to detect forest spatial pattern types.(2)Smooth processing of 3D terrain model:All kinds of burrs and discontinuous blocks often appear in the completed 3D terrain model,which cause the 3D terrain model rough and smoothness poor,which seriously affects the display effect and user experience,Therefore,proposed a smoothing method for 3D terrain model.For DEM model data perform the forward and inverse operations from two directions,At the same time,set relevant parameters according to the user’s smoothing requirements;Using the DEM model data after smoothing operation,the 3D terrain model is generated,that is,completed the smooth processing of 3D terrain model.The results show that the 3D terrain model after smoothing operation has a good visual effect and does not change the trend of the ridge line,it is very important for the quartel line and ridge line alignment of the forest type map.This research resulted in a unique algorithm for the construction of 3D virtual forest,for which a patent was granted.(3)Display control of 3D terrain model:In order to effectively balance the conflict between computer speed and visual effect and enhance user experience,propose a display control method for 3D terrain model.Generate the first 3D terrain model by obtaining DEM model data.The relative height of terrain is calculated by DEM model data.Convert the variation of mouse or keyboard operation to obtain the observation height of the current field of view.The height ratio is obtained using observation height and the relative height of the terrain;According to the height ratio,adjust the sampling span of the spatial polygon corresponding to the current field of view;Finally,sample the space polygons in the current view area according to the adjusted sampling span,and the second 3D terrain model is displayed according to the sampled space polygons,that is,the display control of the 3D terrain model is realized.In short,the display control method of the 3D terrain model is when the user pulls up the angle of view,balanced the computation load by increasing the sampling span and neutralizing the polygon number in space;when the user lowers the angle of view,by reducing the sampling span,enhanced the visual effect by displaying more details of 3D terrain without increasing the amount of computation.(4)Application of innovative methods and technologies:Innovative technologies and methods such as the detection of forest spatial pattern,the smooth processing of 3D terrain model and the display control of 3D terrain model are applied to the design of 3D virtual forest system,have achieved the expected results,which further proves the correctness and feasibility of innovative technologies and methods such as forest spatial pattern detection,3D terrain model smoothing,3D terrain model display control and so on.As a new technical means of forest resource management---this 3D virtual forest,it can efficiently and accurately realize three-dimensional forest display and analysis,and provide intuitive and powerful basis for forestry production decision-making.It will play an active role in protecting the healthy ecological environment and promoting the stable development of forestry.