近年来，随着地理信息技术的不断发展，GIS系统被广泛地应用于各个领域。然而GIS系统仍然面临着很多问题，目前多数厂商的GIS系统仍然以处理二维数据模型为主，其在地理空间信息的展示和分析方面具有很大的局限性，很难满足人们对城市规划与管理、地下地质建模、采矿与石油开发等领域的应用需求。另外，基于C/S架构的GIS系统需要为不同的操作系统分别提供相应版本的GIS客户端，这在一定程度上加大了GIS客户端的开发和管理难度。因此，对跨平台的三维GIS客户端进行研究和开发具有重要意义。 本文针对以上GIS系统所存在的问题提出了一种解决方案，即基于Cesium的WebGIS三维客户端。Cesium是开源的JavaScript库，其实现了在浏览器中展示三维虚拟地球的功能。同时，Cesium采用B/S架构且遵循WebGL三维绘图标准，具有二三维一体化、跨平台、计算精度高等优点。本文围绕Cesium所做的研究工作和创新点包括以下几个方面。 1.分析研究了Cesium开源库所提供的诸如影像图层、高程图层、几何要素等功能，并在项目中灵活运用。 2.通过分析Cesium库的源代码对三维场景的地图地形可视化技术进行了研究和总结，理清楚了地图地形可视化过程中瓦片相关调度算法的实现以及地图地形可视化的核心流程。 3.通过分析Cesium库的源代码对三维场景的矢量要素可视化技术进行了研究和总结，理清楚了静态矢量要素和动态矢量要素可视化的核心流程以及矢量要素随时间动态变化的实现原理。 4.在研究了Cesium可视化关键技术的基础上设计实现了GIS相关模块，包括图层目录树及管理模块、地理网格模块、拉框查询模块、矢量要素点选冒泡模块及交互式要素标注模块，并对这些模块进行了功能测试。 本文所提出的基于Cesium的三维客户端既结合了WebGIS跨平台、开发效率高、易于扩展等优点，又结合了三维客户端地理空间信息展示直观和空间分析功能强大等优点。经测试，本文所设计实现的Cesium模块运行稳定可靠，方便管理，达到了预期的效果。模块实现的功能对于GIS系统数据的浏览、查询、定位、对比及管理等具有重要意义。

In recent years, with the development of geographic information technology, GIS systems are widely used in various fields. However, GIS system is still facing a lot of problems. At present, most GIS systems of manufacturers to handle two-dimensional data model is still dominated, it has significant limitations in the display and analysis of geospatial information, it is difficult to meet the application needs of people for city planning and management, modeling of subsurface geology, mining and oil development in areas such as. In addition, GIS systems based on C/S architecture need to provide the GIS client of appropriate version for different operating system respectively, which increases the difficulty of developing and managing GIS client in a certain extent. Therefore, the research and development of cross-platform 3D GIS client has an important significance. This paper proposes a solution against the above problems existing in GIS system, which is Cesium-based WebGIS 3D Client. Cesium is an open source JavaScript library that implements a functionality of displaying three-dimensional virtual globe in browser. At the same time, Cesium uses B/S architecture and follows the WebGL 3D graphics standard, with the advantages of two or three dimensional integration, cross-platform, computing with high precision. In this paper, the research work done and innovations about Cesium include the following aspects. 1.The functionalities of the open source library Cesium have been analysed and studied, such as image layers, elevation layers, geometric elements and so on. And they were flexible used in the project. 2.Through the analysis of Cesium library source code, the visualization technology of map terrain in 3D scene has been studied and summarized. The implementation of scheduling algorithm related to tile in the process has been cleared. 3.Through the analysis of Cesium library source code, the visualization technology of vector elements in 3D scene has been studied and summarized. The core processes of the visualization of static vector elements and dynamic vector elements have been cleared. The principle of vector elements changing with time has been cleared as well. 4.Modules related to GIS have been designed and implemented on the basis of the study of Cesium visualization technologies, such as layer tree and management module, geographic grid module, box query module, feature bubbling module and interactive feature labeling module. And these modules have been tested. Cesium-based three-dimensional client proposed in this paper not only combines the advantages of WebGIS cross-platform, development with high efficiency, easy expansion, but also combines the advantages of three-dimensional client displaying spatial information intuitively and analysing spatial information powerfully. After testing, Cesium modules designed and implemented in this paper is reliable and manageable, achieving the desired effect. The functionalities of the modules implemented have an important significance for browsing, querying, locating, contrasting and managing GIS data.