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。     

基于WebGL的三维虚拟地球系统设计与实现

传统的三维虚拟地球基于插件实现Web客户端,难以进行跨平台的应用。对此,本文基于Web GL这一跨平台的Web三维图形开发环境,首先构建了Browse/Server模式下的多层体系结构,探讨了基于Web GL的三维虚拟地球绘制关键技术,主要包括Java Script的内存管理和Web端瓦片四叉树调用过程中的缓存管理。最后开发了实验系统,验证了该方法的可行性和有效性。     

数字海洋应用服务系统构建及关键技术研究

我国首次探索了"数字海洋"从科学概念到工程实体的建设实践,经过系统建设和运行过程取得了显著成果,同时存在的问题逐渐显现出来.本研究总结了数字海洋原型系统存在的问题,在此基础上,开展了数字海洋应用服务系统系统架构设计,功能研发以及关键技术研究.通过实践证明,系统在数据共享、信息集成和可视化表达等方面具有良好的应用前景.     

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。     

一种园林火灾智能检测与定位系统的基本方案研究

介绍了红外检测传感器的检测原理；基于模糊理论，研究了传感器检测信息的处理方法；提出了用系流气球平台代替园林火灾观测嘹望台，应用GPS与红外检测器结合来实现园林火灾的自动监测和定位；建立了园林火灾智能监测系统设计框架。     

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。