An efficient method for rendering linear symbols on 3D terrain using a shader language

With the extensive application of virtual geographic environments and the rapid development of 3D visualization analysis, the rendering of complex vector lines has attracted significant attention. Although there are many rendering algorithms in 3D geographic information system (GIS), they are not sufficiently flexible to meet the requirements for rendering linear symbols composed of diverse colors and shapes. However, the interactive rendering of a scene and the accuracy of the symbols are important components for large-scale, complex vector lines. In this paper, we propose a graphics processing unit (GPU)-accelerated algorithm for rendering linear symbols on 3D terrain. Symbol rendering is embedded within the terrain-rendering process, and vector lines are encoded in a 3D texture and then transferred to the GPU. A set of visual properties are used to enrich the expression of symbols with the help of geometric operations in the fragment shader. A series of experiments demonstrate that the proposed method can be utilized for drawing various pixel-exact linear symbols and can achieve real-time rendering efficiency.     

浅谈基于虚拟参考站(VRS)的RTK

随着测绘技术的不断进步,GPS实时动态定位技术(RTK)在测绘领域的应用日益广泛,而基于VRS(虚拟参考站Virtual Reference Station)技术的出现,更是为RTK测量提供了新的技术平台,给测量行业带来了革命性的变化。本文结合实例简要介绍了基于VRS的RTK在测绘领域的应用,阐述了其优越性和不足之处。     

泡沫覆盖的随机粗糙海面的双站散射和热辐射

从双尺度随机粗糙面的散射理论和矢量辐射传输理论出发，将具有白帽泡沫覆盖的风驱海面模拟成一层离散球形粒子下垫双尺度随机粗糙界面的复合模型．利用Ｐｉｅｒｓｏｎ的半经验海洋波高谱和修正的Ｃｏｘ和Ｍｕｎｋ的坡度分布函数，推导了强风驱使下白帽泡沫覆盖的随机起伏海面的双站散射系数和热发射率，得到了极化的双站散射和热发射与海面各物理参数之间定量的函数关系．数值计算的结果与已有的海洋遥感实验数据进行了比较和讨论．     

HyLogger-3, a visible to shortwave and thermal infrared reflectance spectrometer system for drill core logging: functional description

Australian Geological Surveys are the custodians of a major national asset in the form of historically drilled and archived drill cores of the top few kilometres of the continent acquired by government agencies and companies over many decades. The AuScope National Virtual Core Library (NVCL) component of the AuScope Earth Model comprises geological/rock samples, technology, people and database/delivery infrastructure located in six nationally distributed nodes and is aimed at extracting additional value from this asset. The technology components of the NVCL comprise an integrated suite of hardware (HyLogger-3) and software (TSG-Core) systems for the imaging and hyperspectral characterisation of drill cores in their original core trays and the interpretation of their contained oxide, carbonate, hydrous and anhydrous silicate mineralogy. The HyLogger-3 includes state-of-the-art Fourier Transform Spectrometers that continuously measure calibrated spectral reflectance from nominal 10 by 18 mm fields of view. These spectra are in turn passed through a series of automatic and semi-automatic pre-processing and mineralogical unmixing algorithms. These, along with numerous other tools in TSG-Core, output a variety of mineralogical and image products for use by scientists in many branches of the earth sciences. This paper provides a functional overview of the HyLogging hardware and software tools available in each of Australia's Geological Surveys.     

基于OpenGL的三维路线查询系统研究

目前大部分查询路径的系统都是基于二维的,GoogleEarth的出现将路径查询系统引入到了三维的世界,但GoogleEarth是以鸟瞰的方式向人们展示路径的,不符合人一般行走过程的视觉习惯。本文介绍利用VC 6．0、MapObjects和OpenGL来实现一个能虚拟显示行走过程的三维空间查询系统,从而对OpenGL在GIS软件中的应用进行了探讨。     

基于VC++的虚拟现实可视化工具的设计与实现

随着网络技术发展，虚拟现实建模语言(VRML)被广泛用于在因特网上构建虚拟境界。由于VRML语言自身的特点，虚拟现实的制作十分繁琐。如何提高开发的效率，具有很重要的意义。本文在分析和研究了VRML对象的基础上，实现了虚拟现实的可视化开发工具，并给出风华园虚拟系统的应用实例。     

结合KSTEST统计检验方法的联合像素时序干涉SAR处理技术

联合像素干涉SAR处理技术属于第二代时序干涉SAR技术,技术流程分为3步：联合像素信号模型建立,拟合优度检验,空域自适应滤波。本文在一维KSTEST统计检验方法基础上,提出了基于多维联合像素的非参数拟合优度检验方法,利用实测数据将该方法与传统的多时相干涉SAR技术结果对比,使形变监测点空间密度得到有效提升,形变监测能力得到进一步提高。     

基于虚拟现实的远海岛礁地理环境物联网监测系统设计与实现

针对远海岛礁生态环境监测与保护无法满足环境要素实时监测与智能处置需求,在分析现有环境要素感知与智能危机应对技术的基础上,融合虚拟现实和物联网技术,研发了远海岛礁地理环境实时监测系统。该系统依据传感器类型设计存储表格,以支持多源异构传感器数据统一组织与管理;利用物联网技术采集远海岛礁水体、土壤、气象、植被等地理环境数据,实现了感知数据的无线传输、接入与远程数据存储;利用虚拟现实技术,在远海岛礁三维场景建模的基础上,实现了场景漫游与互操作,并结合物联网技术实现了虚实一体化的智能感应设备的远程控制。基于该系统,管理人员不仅能获取远海岛礁实时地理环境数据,还能远程操作智能感应设备(如植被浇灌水阀),解决了以往需要人工往返岛礁的管理问题,有效地提高了工作效率。     

虚拟局域网技术在信息网络管理中的应用

根据新疆维吾尔自治区地震局局域网的现状和存在的问题,将虚拟局域网技术引用到新疆维吾尔自治区地震局局域网管理中,分析和讨论建立虚拟局域网的实现方法和实际意义,解决目前局域网存在的问题,从而提高局域网网络管理和网络服务质量。     

中国区域虚拟水战略优势度评价

提出虚拟水战略优势度的概念并对其概念内涵及影响因素进行分析,从4个方面构建包含12个具体指标的综合定量评价指标体系;运用数学方法对中国31个省级行政区虚拟水战略优势度进行定量评价.发现中国虚拟水战略优势度存在显著的地域差异,区域优势度等级存在"两头多,中间少"的结构特点和"东部高、西部低","南部和北部高、中间低"带状空间分布规律.其中北方4省市和东南8省区优势度最大,是全球虚拟水战略背景对其影响最深远的区域,也是中国虚拟水研究及虚拟水战略实践的关键区域.