基于Silververlight的3D数字地球模型构建关键技术及应用研究

【作者】 刘阿亭；

【导师】 兰小机；

【作者基本信息】 江西理工大学 ， 地图学与地理信息系统， 2011， 硕士

【摘要】 随着Windows7的普及,以及iPhone的争艳,可以说明人们已经对传统意义上的窗体程序产生了一定程度上的审美疲劳,而在呈现端的要求越来越高。自Silverlight与Flex推出后,在互联网上引起了编写精美的富客户端网页热潮。随着GIS的普及,越来越多的人生产活动依赖于静态网页形式的地图服务。但是到目前为止,GIS网页端地图服务呈现展示依然进展不大,传统的2D地图服务已很难再冲击人们的眼球,再加上静态网页模式的运算和解析全部依赖于服务器,而客户端机器不能参与运算作用,然而基于Silverlight的3D数字地球在客户机子上显示效果不仅有极大增强而且很大程度提高了图形运算能力。对于GIS这种数据量大以及需要复杂的空间运算能力的需求,富客户端对于静态页面形式的优势尽显出来。鉴于此,本文研究了基于Silverlight3D数字地球构建的关键技术进行了研究,包括2D坐标系变换和图形操作、影像数据的操作、3D球面构建以及2D数据投影到3D表面。即实现了3D地球的底层构建也实现了3D数字地球的呈现。本文主要研究工作包括:1)目前3D数字地球的研究工作主要集中在客户端程序方面,在网页端只有2D的地图服务,现有文献中很少涉及到具体3D数字地球创建,对于富客户端的3D数字地球都存在于理论阶段。本文从底层进行研究,并且涉及到图形的多个方面,实现了在三维球面上对GIS数据进行展示。2)分析影像数据的特点,设计了一整个流程对影像数据进行操作,包括:为影像数据建立金字塔模型、提取合并、分割、加壳和入库等操作。3)为了构建3D环境,研究了3D坐标的变换,影响球面显示的关键元素,最后四元数对球面旋转变换时误差的修正。4)经过了3D球面的构建,研究了如何把2D数据投影到3D地球表面,这里完成了经纬度映射到球面的反算,并研究了多纹理和单纹理点密度坐标控制法。5)最后以Visual Studio2010为开发工具,运用面向对象的方法,基于Silverlight富客户端呈现技术从底层开发了一个3D数字地球演示系统,实现了图形显示、影像多层分级,3D地球的漫游、地球自转等操作,并结合空间数据库来管理维护空间数据。更多还原

【Abstract】 With the popularity of Windows7 and the blooming of the iPhone, we can sense that people have a certain degree of aesthetic fatigue on the traditional forms program,and have higher demand on the present side. Since the release of Silverlight and Flex, the boom of writing beautiful rich-client Web has beening presented on the Internet. With the popularity of GIS, more and more human production activities rely on map services in the form of static pages. But GIS Web Map Service client display has not made big progress up to now, the traditional 2D map service can hardly catch people’s attention, combined with that the operation and resolution of static page mode all depend on the server, and the client machine can not participate in operational role, while Silverlight-based 3D digital earth not only greatly enhanced the display effect on the client machine, but also improved graphic operation ability to a large degree. To GIS mass data which require complex spatial operation ability, compared to the form of static pages, the advantage of rich-client is significant. In view of this, we study the key technology of the construction of Silverlight-based 3D digital earth, including 2D coordinate transformation and graphic operations, the operation of image data, the construction of 3D spherical surface and 2D data projection to 3D surface. This paper has realized the bottom building of 3D digital earth as well as the display of it. This paper’s main research work include:1)The current 3D digital earth research mainly is focused on the client side,on the web side there is only 2D map service, the existing literature are rarely involved in creating 3D digital earth, for the rich clients 3D digital earth research is still stay at a theory phase . This article is based on the bottom, involving several suspect of the graphic. This article includes the implement of displaying GIS data on the 3D sphere.2) This article is going to talk about the analysis of the characteristics of image data, designing a flow, which includs the pyramid model for the image data set, extract merge, split, packers and storage and some other operations for managing image data.3)In order to build the 3D environment, it would be necessary to make some research on the 3D coordinate transformation, the key elements that affect the sphere displaying, the error correction of the sphere rotation transform by the last for quaternion.4)After the construction of 3D sphere, this article discussed how to porject the 2D data onto the 3D earth surface, this procedure complete the inverse compute from latitude and longitude to sphere. Further more, this article discussed the method of controlling the point density coordinates of multi-texture and single- texture.5)Finally, developed a system from the bottom that shows the 3D data earth. The system take Visual Studio2010 as the development tool and use the object-oriented approach and is based on Silverlight rich-client rendering technology. The system which combines the spatial database to manage the maintenance of spatial data contains functions like graphical display, multi-image classification, 3D earth panning, the earth rotation and other operations.更多还原