基于外存和网络的球形地形绘制与漫游关键技术研究
发布时间：2018-09-17 13:33
【摘要】：近年来,基于全球性的三维地形漫游系统受到大家的热切关注,已广泛应用于地理信息系统(GIS)、国防军事、城市规划等领域。然而,随着现代数据采集能力的提升和人们对需求质量的进一步提高,绘制全球性的三维地形漫游系统所需处理的数据已经达到了几十、几百GB甚至是TB级了。那么如何在计算机硬件条件有限的情况下实现大规模球形地形实时绘制就成了当前的研究热点。本文围绕球形地形数据组织、球形地形数据调度和球形地形漫游三大模块,对基于外存和网络的球形地形绘制与漫游关键技术展开研究。本文的主要工作和研究成果包括以下几个方面:(1)针对球形地形数据组织进行了深入细致的研究。设计了一种针对球形地形的四叉树多分辨率地面构建模型以及相对应的地形块编码方式;综合比较了文件和数据库两种数据存储与管理方式的优劣,选定了以文件的方式来存储和管理地形数据;提出了地形块数据组合的数据组织优化方式来减少数据I/O时间,同时根据球形地形高程数据的特有情况,剔除了一部分高程数据,减少了地形数据处理量,提高了地形绘制效率。(2)针对球形地形数据调度进行了深入细致的研究。在基于平面地形的视锥裁剪技术基础上,提出了一种改进的基于球形地形的视锥裁剪技术;在权衡了绘制效率和绘制效果后,设计了一种粗略估算节点投影面积的计算方法来做节点误差评价,并实现了球形地形多分辨率的节点遍历和更新算法;提供了数据预加载和多线程数据调度两种地形绘制加速方案;另外,为了增强球形地形绘制系统的应用范围,还设计了一种本地和网络相结合的数据调度方式。(3)针对球形地形漫游做了较为详尽的研究。其中包括视线平移、球面平移、球体普通旋转、球体加速旋转、物体观察中的视线追踪和位置追踪、各种情况下的视点切换过渡等等。
[Abstract]:In recent years, 3D terrain roaming system based on global has been paid close attention to, and has been widely used in (GIS), national defense, urban planning and other fields. However, with the improvement of modern data acquisition ability and the further improvement of people's demand for quality, the data needed to be processed by the global 3D terrain roaming system has reached tens, hundreds of GB or even TB level. So how to realize real-time rendering of large-scale spherical terrain under limited computer hardware conditions has become a hot research topic at present. This paper focuses on three modules: spherical terrain data organization, spherical terrain data scheduling and spherical terrain roaming. The key technologies of spherical terrain rendering and roaming based on external memory and network are studied in this paper. The main work and research results of this paper include the following aspects: (1) the detailed research on spherical topographic data organization is carried out. A quadtree multi-resolution ground construction model for spherical terrain and the corresponding terrain block coding method are designed, and the advantages and disadvantages of file and database data storage and management are comprehensively compared. In this paper, we choose to store and manage topographic data in the form of files, propose an optimized method of data organization and optimization of topographic block data combination to reduce the I / O time of data, and eliminate a part of elevation data according to the special situation of spherical topographic elevation data. The processing capacity of terrain data is reduced and the efficiency of terrain rendering is improved. (2) the detailed research on the scheduling of spherical terrain data is carried out. In this paper, an improved conical clipping technique based on spherical terrain is proposed, which is based on planar terrain, and after balancing the rendering efficiency and rendering effect, In this paper, a rough calculation method of node projection area is designed to evaluate the node error, and the node traversal and update algorithm with multi-resolution of spherical terrain is realized. In order to enhance the application scope of spherical terrain rendering system, two kinds of accelerated topographic rendering schemes, data preloading and multithread data scheduling, are provided. A data scheduling method combining local and network is also designed. (3) A detailed study on spherical terrain roaming is carried out. It includes line of sight translation, spherical translation, sphere general rotation, sphere acceleration rotation, line of sight tracking and position tracking in object observation, transition of view switching in various situations, etc.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P208;TP391.41
本文编号：2246076
[Abstract]:In recent years, 3D terrain roaming system based on global has been paid close attention to, and has been widely used in (GIS), national defense, urban planning and other fields. However, with the improvement of modern data acquisition ability and the further improvement of people's demand for quality, the data needed to be processed by the global 3D terrain roaming system has reached tens, hundreds of GB or even TB level. So how to realize real-time rendering of large-scale spherical terrain under limited computer hardware conditions has become a hot research topic at present. This paper focuses on three modules: spherical terrain data organization, spherical terrain data scheduling and spherical terrain roaming. The key technologies of spherical terrain rendering and roaming based on external memory and network are studied in this paper. The main work and research results of this paper include the following aspects: (1) the detailed research on spherical topographic data organization is carried out. A quadtree multi-resolution ground construction model for spherical terrain and the corresponding terrain block coding method are designed, and the advantages and disadvantages of file and database data storage and management are comprehensively compared. In this paper, we choose to store and manage topographic data in the form of files, propose an optimized method of data organization and optimization of topographic block data combination to reduce the I / O time of data, and eliminate a part of elevation data according to the special situation of spherical topographic elevation data. The processing capacity of terrain data is reduced and the efficiency of terrain rendering is improved. (2) the detailed research on the scheduling of spherical terrain data is carried out. In this paper, an improved conical clipping technique based on spherical terrain is proposed, which is based on planar terrain, and after balancing the rendering efficiency and rendering effect, In this paper, a rough calculation method of node projection area is designed to evaluate the node error, and the node traversal and update algorithm with multi-resolution of spherical terrain is realized. In order to enhance the application scope of spherical terrain rendering system, two kinds of accelerated topographic rendering schemes, data preloading and multithread data scheduling, are provided. A data scheduling method combining local and network is also designed. (3) A detailed study on spherical terrain roaming is carried out. It includes line of sight translation, spherical translation, sphere general rotation, sphere acceleration rotation, line of sight tracking and position tracking in object observation, transition of view switching in various situations, etc.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P208;TP391.41
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