【作者】 孙海洪；

【导师】 罗传文；

【作者基本信息】 东北林业大学 ， 森林经理学， 2011， 硕士

【摘要】 地理信息技术发展到现在,已经应用到了各行各业。随着二维GIS的技术的不断成熟,各行业的应用也趋于稳定,基于二维GIS的三维地理信息技术开始在全国各个行业中迅速的发展起来。地理信息技术从二维,到二点五维,再到三维的一个过渡的时代已经来临。从现在的形式不难看出,将来的几年将是三维地理信息技术成熟的关键时刻。本文着重介绍地理信息技术在林业上的应用,利用三维地理信息技术来构建三维虚拟林相。实现三维林场的显示、漫游、和缩放功能。在吸取三维计算机图形学、计算几何、科学计算可视化、虚拟现实、计算机网络的先进理论和技术成果的基础上,围绕地形三维可视化及其实时绘制技术中的数字地形模型、三维真实感地形生成、分形地形模拟、地形简化和多分辨率表达等技术,本文针对当前三维可视化及其实时绘制技术的研究现状对基于网络的三维地形可视化等核心技术内容进行讨论与研究,目标是建立林场三维可视化及其实时绘制技术在现有相关学科技术成果上实现的基本理论和技术框架。本研究以上甘岭林场为试验区,基础数据采用矢量化的等高线数据,利用ArcMap软件进行插值,栅格化,DEM提取等过程来提取地形数据。结合十一种假设的树木模型和一个设定的针叶树树线高度来控制模型的生成,使得模型更加合理。在方法上,借鉴前人的加载方法,在地形数据的格式上采用独有的Raw格式数据作为高程数据,树木的大小和位置采用随机算法,在高度高于拟定值2/3*H(H为最大程)的时候强制将随机纹理设定为针叶树纹理。完成后的模型运行结果和现实效果表明,本研究所采用的方法合理,有效地减少了地形加载的时间,现实效果上也比较贴近现实,代码实现了可移植性,达到了预期的目标。更多还原

【Abstract】 Geographic technology has been used on series of fields. The methods are becoming stable as mellowing of the 2-Demension GIS.3-Demension technology based on 2D GIS is spreading to every corner. The transitionary period of Geographic technology has airmailing after the 2-Demension and 2.5-Demension period. We can speculate that there is a crucial moment in several years from the situation now. In this thesis, the emphasis is giving an application of 3D GIS in the field of forestry, Building a roaming 3D model of forestry. The program can realize the function of displaying roaming and zooming in and out. Aiming at the present situation of 3D realizing technology, after absorbing the computer graph technology, compute geometry technology, visual realization technology computer network technology the thesis’s aim is to build a frame of 3D Forestry model, using the technology in my project. Besides, in this thesis we deeply probe the technology of Real-time building model, truth virtual building model, branching model, simplifying of the code and the expression of multi resolution.This paper uses ShangGanling Forest Farm as the search area and the contour as the base data. In the paper I realized the interpolation rasterization and DEM Extracting via the software ArcMap. The terrain was built by the DEM and the assumptions trees and on the top of the mountain the tree style was defined as the conifer. Then the model seems reasonable. There have three methods to make the model difference to the others. First, I use the Raw data as the base DEM. Second, the size, location and the styles of the tree are random. The result the model seems that the methods I used in the research was reasonable. It reached the level of the aim and the effect closed to the reality. By using these methods the time loading the DEM was reduced. By the same the code can be used in any project which has the function in the research.更多还原