虚拟地理环境中气候环境模拟研究

以图形纹理映射作为主要技术,结合粒子系统、Billboard技术及纹理移动技术,探讨了气候环境建模的方法,实现了各种气候环境的真实模拟。     

基于多重变换组合的动态地图符号设计

采用面向对象的设计方法,将符号的状态描述（参量）与过程操作（对不同参量实施不同变换）封装,采用关键帧-层-图元-几何/非几何属性结构进行符号组织,从而将地图符号的时间维信息纳入到符号设计之中,建立了不同的变化速率模型,实现属性的动态变化;通过图元与图元之间的二维Morph函数变换矩阵,结合仿射变换,对符号的几何信息进行快速提取,从而实现了符号的动态显示.     

基于数据引擎思想的GIS数据集成与共享

通过对数据库系统数据共享的实现原理进行分析，探讨了采用数据引擎思想实现GIS数据的集成与共享的原理与方法。并在VC 环境下，以标准地球空间数据交换格式(VCT)作为基础，实现了常用GIS数据的集成与共享。     

基于模板的DEM快速可视化

为了满足对海量数据三维实时动态浏览的需要,采用地形分块技术,形成了地形分块模板、地形整合模板、视点相关模板,建立了基于模板技术的地形快速可视化流程,并在VC 平台下,采用OpenGL渲染引擎实现了大规模地形的快速无缝漫游。     

地图可视化中符号智能配置研究

本文在符号库设计的基础上,利用现有的符号库对地图要素进行符号化配置,探讨了符号智能配置过程中常用的绘制算法,研究了符号配置知识库,并针对符号配置中可能出现的冲突问题,进行分析和归纳,利用空间关系和Voronoi图对冲突进行研究,并对其提出了解决方案。     

VARIATION OF PRECIPITATION DURING WINTER AS A CAUSE OF SUSTAINED DROUGHT IN GUANGDONG DURING THE PAST 50 YEARS

The variation characteristics of precipitation during the winter (between October and the following March, to be referred to as just “the winter” hereafter) in Guangdong province during the past 50 years (from 1957 to 2006) and the relationship with Pacific SST are studied using the methods of Empirical Orthogonal Function (EOF) analysis, wavelet analysis, and correlation analysis. The results show that The Guangdong precipitation during the winter exhibits quasi-periodic significant oscillations of 40 years and 2 years; rainfall is less from the end of the 1950s to the start of the 1970s and from the end of the 1990s to the present than from the mid 1970s to the mid 1990s. The frequency of sustained drought is more than sustained flooding during the winter. The Guangdong precipitation during this time period is in significantly positive correlation to the equatorial central and eastern Pacific SST, but in a significantly negative correlation with the western and northern Pacific SST east of the Philippine Sea. 61.5% of the sustained drought occurred in the phase of negative anomalies of the Ni?o3.4 index and 38.5% in the phase of positive ones. A composite analysis of atmospheric circulation is performed for the positive and negative phases of the Ni?o3.4 region associated with the sustained drought. The results showed that a weak polar vortex, a strong trough in Europe and a ridge near Balkhash Lake, active cold air and consistent northerly wind anomalies controlling Guangdong at low levels, an inactive westerly low disturbance in the low-mid latitude of the Asian continent, and a weak southern branch westerly trough, are all mutual causes for the sustained drought.     

基于GIS的水文信息系统的设计与实现

本文在分析GIS与水文领域相结合的基础上，详细阐述了基于GIS的水文信息系统的需求分析，功能及数据库设计，构建了系统的总体架构。然后，采用Visual C＋＋平台进行了系统软件开发，并从图文查询、统计分析、报表显示等多方面讨论GIS技术在水文信息系统中的特色应用。     

复杂线状符号的设计及优化算法研究

针对地图线状符号中的需求，提出了利用自定义线型设计线状符号的新方法，以解决常规线型符号绘制的问题。此外，考虑到线状符号在拐角处易产生严重变形以及出现断裂、自相交等情况，提出了采用符号自适应性及双仿射变换方法的解决途径，实现符号化绘制，增强符号的可视化效果。     

数字地图注记中特殊矢量字体的显示

在VC^ 开发平台下，运用矩阵变换对矢量地图注记进行坐标变换，实现地图注记中特殊矢量字体(如左斜、耸肩字体)的存贮与显示。     

VC++平台下多媒体电子地图集演示系统的设计与实现

分析了多媒体电子地图相对纸质地图的优点以及电子地图的两种开发方式,并在此基础上,给出了多媒体电子地图集演示系统的总体结构以及实现的关键技术点,并论述了各关键技术点的解决方法,最后在VC 平台下设计并实现了多媒体电子地图集演示系统.