基于VTK的二三维GIS核心组件的开发

发布时间：2018-02-21 19:23

本文关键词： GIS VTK 二三维一体化金字塔可视范围 LOD选择算法 GPU 顶点平滑过渡算法 Goophy8.1　出处：《浙江大学》2013年硕士论文　论文类型：学位论文

【摘要】：在二三维GIS一体化的全新技术理念下,研究如何在同一平台下使用同一绘制引擎展示二维和三维地图具有非常的意义。本文利用VTK作为绘制引擎,开发了一套二三维GIs的核心组件,以同时支持二维栅格地图、二维矢量地图和三维地形图。文中对二三维地理数据的预处理、数据的组织和存储、内存管理、地理数据的选择和实时绘制这一整套流程都做了详细描述。本文的研究重点是对二维栅格地图和三维地形图的实时绘制技术。实现大规模二维栅格地图实时绘制的步骤可概括为：第一步,针对不同规模的单张影像输入和多张影像输入分别执行不同的金字塔切割算法；第二步,建立金字塔的四叉树索引,并将需要绘制的瓦片节点进行内存缓冲管理；第三步,查找符合给定地理范围的瓦片节点,并以纹理的方式用VTK进行绘制。三维地形图实时绘制技术的研究与实现是本文的难点,主要体现在三个阶段：数据预处理阶段,提出将高度图、法向量图和纹理图经分层分块后以二进制文件流的形式存储在Final文件中；地形节点选择阶段,提出了基于可视范围的空间地形节点的LOD选择算法,综合考虑了视点高度和地形节点的空间范围；渲染阶段,在每层的可视范围中划分出一段过渡区域,并把地形接缝的处理粒度从地形块缩小到顶点,设计出了适合GPU计算的顶点平滑过渡算法。最后,本文在Goophy8.1平台下开发出了基于VTK的二三维GIS所有的核心组件,该系列组件可以被跨语言、跨平台使用,并经实验证明,对大规模二维栅格地图和三维地形的实时绘制表现出良好的效果和性能。
[Abstract]:Under the new technology idea of the integration of 2D and 3D GIS, it is very important to study how to use the same drawing engine to display 2D and 3D maps on the same platform. In this paper, VTK is used as the rendering engine. A set of core components of 2D and 3D GIs are developed to support 2D grid map, 2D vector map and 3D topographic map at the same time. The selection and real-time rendering of geographic data are described in detail. This paper focuses on the real-time rendering of two-dimensional raster maps and 3D topographic maps. The steps to realize the real-time rendering of large-scale two-dimensional raster map can be summarized as follows: first, different pyramid cutting algorithms are performed for single image input and multiple image input of different sizes; The quadtree index of the pyramids is built and the tile nodes that need to be drawn are managed by memory buffer. The third step is to find the tile nodes in a given geographical range and draw them with VTK in the form of texture. The research and implementation of 3D topographic map real-time rendering technology is the difficulty of this paper, which is mainly reflected in three stages: data preprocessing stage, the proposed height map, The normal vector graph and texture map are stored in the Final file as binary file stream after stratified and partitioned, and the LOD selection algorithm based on visual range is proposed in the stage of terrain node selection. The view height and the spatial range of terrain nodes are considered synthetically, and in the rendering stage, a transition area is divided in the visual range of each layer, and the processing granularity of the terrain joint is reduced from the terrain block to the vertex. A vertex smooth transition algorithm suitable for GPU computation is designed. Finally, this paper develops all the core components of 2D and 3D GIS based on VTK based on Goophy8.1 platform. This series of components can be used across languages and platforms, and it has been proved by experiments. It shows good effect and performance for large scale 2D raster map and 3D terrain real-time rendering.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TP391.41;P208

【参考文献】