CityEngine CGA支持下的苗族特色民居三维建模

少数民族民居是中华民族文化的重要组成部分,而在现今民族大融合的背景下,传统少数民族建筑的传承和发展正呈现衰退之势,采用三维建模技术对少数民族民居进行数字化保存意义重大。苗族民居造型复杂,具有独特的吊脚楼结构,给规则建模带来困难。为此,本文以CityEngine软件为建模平台,巧妙地组合与运用挤出、拆分、平移等基础函数,编写了苗族民居底层支柱、二层主屋和歇山型屋顶的规则,完整地实现了苗族典型民居的规则建模,并实现了民居样式的动态调整与民族村寨的快速生成。研究结果表明,基于CGA规则对复杂的民族民居三维建模方法可行,为数字化保存少数民族民居提供了便捷的方式。     

A comparative analysis of pansharpening techniques on QuickBird and WorldView-3 images

Nowadays, different image pansharpening methods are available, which combine the strengths of different satellite images that have different spectral and spatial resolutions. These different image fusion methods, however, add spectral and spatial distortions to the resultant images depending on the required context. Therefore, a careful selection of the fusion method is required. Simultaneously, it is also essential that the fusion technique should be efficient to cope with the large data. In this paper, we investigated how different pansharpening algorithms perform, when applied to very high-resolution WorldView-3 and QuickBird satellite images effectively and efficiently. We compared these 27 pansharpening techniques in terms of quantitative analysis, visual inspection and computational complexity, which has not previously been formally tested. In addition, 12 different image quality metrics available in literature are used for quantitative analysis purpose.     

3S技术与智能交通

地球空间信息技术是当前世界范围内发展最快的三大重要高新技术之一,随着其不断地发展和完善,其基础理论和技术方法已经日趋成熟,并正在从规划、国土、测绘、军事等专业应用向社会生活的众多行业和领域渗透和拓展,3S技术在交通领域的应用已成为当前国内外研究和应用的热点。着重介绍了地球空间信息技术在道路交通领域的应用背景,阐述了3S技术与道路交通结合的理论支撑和技术方法,进而介绍了其在交通管理、物流管理、智能导航、交通信息服务和交通安全等方面的典型应用,并展望了3S技术在现代交通领域的发展前景。     

随机Dirichlet问题解的调和展开

针对重力学随机Dirichlet问题,通过适当地对边界检验函数的分解,并在随机边界样本空间中提取确定性部分的对偶基,本文将随机Dirichlet问题的一般解展开为一随机系数的调和级数形式。     

基于钻孔数据的三维地质建模与可视化研究

三维地质模型能够完整准确地表达复杂地质现象的边界条件及地质体内含的各种地质构造,直观地再现地质单元的空间展布及其相互关系,最大限度地提高地质分析的直观性和准确性,因此三维地质建模已引起地质、采矿、岩土工程等诸多领域的日益重视。笔者在综合考察多种建模方法的基础上,结合工程实践,提出了一种实用的工程地质三维建模实施方法。该方法以钻孔资料和地质剖面数据为三维地质建模的源数据,允许用户手工修正模型剖面地层分界线,从而实现对建模过程的干预和控制,克服了单纯依靠钻孔数据建模结果不精确且难以修正的问题。最后,通过一个研究实例展示了该方法的实际建模效果。     

基于ArcScene的建筑物日照分析模块的设计与实现

介绍了利用ArcObjects开发、基于ArcScene的建筑物日照分析模块的研制,对各个子模块作了介绍。特别对涉及到的日照分析技术、阴影动态显示、3维建筑设计等技术做了详细的说明。最后对该模块的应用做了简要演示。     

Applications of Lodrigues Matrix in 3D Coordinate Transformation

Three transformation models (Bursa-Wolf, Molodensky, and WTUSM) are generally used between two data systems transformation. The linear models are used when the rotation angles are small; however, when the rotation angles get bigger, model errors will be produced. In this paper, we present a method with three main terms: ① the traditional rotation angles θ , φ ,ψ are substituted with a , b, c which are three re-spective values in the anti-symmetrical or Lodrigues matrix; ② directly and accurately calculating the formula of seven parameters in any value of rotation angles; and ③ a corresponding adjustment model is established. This method does not use the triangle function. Instead it uses addition, subtraction, multiplication and division, and the complexity of the equation is reduced, making the calculation easy and quick.     

基于Oracle Spatial的多元重力场信息数据库的设计与应用

随着地球重力场信息多元化的发展及其应用领域越来越广,科学高效的管理和应用重力场信息数据就显得尤为重要。文中介绍了基于Oracle Spatial技术设计与构建的重力场信息数据库的结构框架,分析了存储数据信息的种类、属性及特点,研究了数据的存储方式。在多元化重力场数据与基础地图数据统一管理的基础上,初步实现了多元化重力场信息的存储、查询、计算、绘图及显示等功能。     

Modeling errors in upward continuation for INS gravity compensation

Accurate upward continuation of gravity anomalies supports future precision, free-inertial navigation systems, since the latter cannot by themselves sense the gravitational field and thus require appropriate gravity compensation. This compensation is in the form of horizontal gravity components. An analysis of the model errors in upward continuation using derivatives of the standard Pizzetti integral solution (spherical approximation) shows that discretization of the data and truncation of the integral are the major sources of error in the predicted horizontal components of the gravity disturbance. The irregular shape of the data boundary, even the relatively rough topography of a simulated mountainous region, has only secondary effect, except when the data resolution is very high (small discretization error). Other errors due to spherical approximation are even less important. The analysis excluded all measurement errors in the gravity anomaly data in order to quantify just the model errors. Based on a consistent gravity field/topographic surface simulation, upward continuation errors in the derivatives of the Pizzetti integral to mean altitudes of about 3,000 and 1,500 m above the mean surface ranged from less than 1 mGal (standard deviation) to less than 2 mGal (standard deviation), respectively, in the case of 2 arcmin data resolution. Least-squares collocation performs better than this, but may require significantly greater computational resources.     

三维地理信息应急指挥系统设计

基于GIS构建的应急指挥系统在应急救灾工作中作用日益突出,本文在应急指挥系统功能需求分析基础上,采用网格和四叉树索引技术构建了统一地理框架平台的海量基础地理信息与应急资源专题数据库,采用C/S架构、插件式模块化思想设计应急指挥系统的总体框架和功能体系,为应急救灾的灾前预警分析、灾中灾情评估、资源调度等工作提供辅助决策支...