三维地理空间中数据库性能优化技术研究

在三维建模与动态仿真项目的开发过程中,随着项目的不断推进,地理空间数据量不断增长,数据的存取日益频繁,三维地理空间数据库凸显出数据存储响应速度过慢、地图浏览等待时间过长的问题。通过对关系数据库性能优化技术、空间数据引擎性能优化技术、ArcGIS服务器性能优化技术实现了三维地理空间数据库性能优化,有效地解决了数据库的性能问题。     

基于GIS的高速公路数据库建立与实现

为了建立和实现高速公路GIS空间数据库,通过设计高速公路的Geodatabase数据模型,采集、整理和处理相关数据,利用ArcGIS＋ArcSDE＋Microsoft SQL Serve模型建立空间数据库和属性数据库,并对空间数据进行管理,从而实现高速公路空间数据的统一存储,为后续开发作数据准备。     

基于GRASS的城市地下管线二三维可视化

设计并构建地下管线综合数据库,利用开源GIS平台GRASS的二维显示模块,读取数据库中存储的管线空间数据来生成并显示管线二维布局图,利用AutoCAD进行管线三维建模,然后运用GRASS的三维模块实现管线空间数据的三维可视化。为实现地下管线信息管理系统中的二、三维信息联动提供一种可行的解决方案,同时为运用开源GIS开发面向行业应用的三维信息管理系统提供一种技术路线与实践经验。     

SuperMap与ArcGIS异构空间数据集成方法研究与实现

针对目前正在开展的“数字城市地理空间框架建设”项目中异构空间数据无缝集成困难、数据难以集成共享等问题,提出一种基于GML的SuperMap与ArcGIS异构空间数据集成方法。项目实验表明,基于GML的SuperMap与ArcGIS异构空间数据集成方法能解决异构空间数据集成共享问题,具有原理简单、编程容易、无缝集成等特点。     

林火扑救指挥系统空间数据库构建

在通过对林火扑救需求分析的基础上,对空间数据库进行合理的设计,将空间数据和专题数据有机地组织和管理起来,应用UML方法设计得出空间数据库对象模型图,基于Geodatabase数据模型,使用CASE工具生成林火扑救指挥系统数据库,有效地提高了数据库的可用性,为林火扑救系统的应用奠定基础。     

浅谈面向对象技术在1:5万战略性矿产远景调查地质图空间数据库建设中的应用

地质图空间数据库建库通过野外手图数据库、图幅PRB数据库、图幅实际材料图数据库、图幅剖面数据库不同阶段数据互通、继承、提取和凝练而形成.其核心是采用在关系数据库理论的基础上,增加了面向对象特性,把面向对象技术与关系理论结合的地质图空间数据建模技术,使面向对象的数据可在关系数据库中存储表达,又克服了关系数据库太简单的缺点.通过云南省叶技-依陇1:5万地质图空间数据库建库实践,阐述了数字地质调查系统地质图空间数据库制作方法流程,分析了地质图空间数据建模技术的实际应用问题.     

VFP中利用SQL和OLE技术增强报表功能

VisualFoxPro是可视化数据库管理系统 ,为数据库应用提供了功能强大的面向对象的开发环境 ,并可以提供管理数据所需的所有工具。但是 ,VisualFoxPro中的报表工具功能比较单一 ,不能适应一些复杂的应用。我们可以利用SQL技术和OLE技术与EXCEL软件相结合 ,来代替报表工具 ,增强VFP中的报表功能 ,设计出适应实际需要的报表     

GIS三维可视化系统的实现

三维可视化是用于显示描述和理解地下及地面诸多地质现象特征的一种工具,随着GIS应用的深入,人们越来越多地要求从真三维空间来处理问题,因此利用地理信息系统及其三维可视化的实现已成为当前的一大研究热点。文章描述了一个GIS三维可视化系统建立的过程,介绍了在三维可视化过程中的关键技术,建立了多分辨率地理模型,最后对系统的实现给出一个实例。     

基于无线网络的GIS数据库系统应用研究

无线GIS是GIS产业发展中一个富于挑战性的研究领域。其中通过ArcSDE作为中间件连接ArcGIS应用程序和SQL关系数据库系统,解决了空间数据及其属性数据的存储和管理。讨论了基于无线网络的GIS数据库系统的相关技术、构成、实现及应用前景。     

应用IDL实现气象数据三维可视化

在三维气象数据分析中,通过灵活运用IDL的三维绘图函数,可实现复杂数据的快速可视化,提高科研人员工作效率。本文系统介绍了IDL中7个三维绘图函数的功能,并以绘制三维云图为例,展示了运用这些函数实现三维可视化的过程。     

Evaluation of the effectiveness of 3D vascular stereoscopic models in anatomy instruction for first year medical students

The head and neck region is one of the most complex areas featured in the medical gross anatomy curriculum. The effectiveness of using three‐dimensional (3D) models to teach anatomy is a topic of much discussion in medical education research. However, the use of 3D stereoscopic models of the head and neck circulation in anatomy education has not been previously studied in detail. This study investigated whether 3D stereoscopic models created from computed tomographic angiography (CTA) data were efficacious teaching tools for the head and neck vascular anatomy. The test subjects were first year medical students at the University of Mississippi Medical Center. The assessment tools included: anatomy knowledge tests (prelearning session knowledge test and postlearning session knowledge test), mental rotation tests (spatial ability; presession MRT and postsession MRT), and a satisfaction survey. Results were analyzed using a Wilcoxon rank‐sum test and linear regression analysis. A total of 39 first year medical students participated in the study. The results indicated that all students who were exposed to the stereoscopic 3D vascular models in 3D learning sessions increased their ability to correctly identify the head and neck vascular anatomy. Most importantly, for students with low‐spatial ability, 3D learning sessions improved postsession knowledge scores to a level comparable to that demonstrated by students with high‐spatial ability indicating that the use of 3D stereoscopic models may be particularly valuable to these students with low‐spatial ability. Anat Sci Educ 10: 34–45. © 2016 American Association of Anatomists.     

Alternative 3D Modeling Approaches Based on Complex Multi-Source Geological Data Interpretation简

Due to the complex nature of multi-source geological data, it is difficult to rebuild every geological struc-ture through a single 3D modeling method. The multi-source data interpretation method put forward in this analysis is based on a database-driven pattern and focuses on the discrete and irregular features of geological data. The geological data from a variety of sources covering a range of accuracy, resolution, quantity and quality are classified and inte-grated according to their reliability and consistency for 3D modeling. The new interpolation-approximation fitting construction algorithm of geological surfaces with the non-uniform rational B-spline （NURBS） technique is then pre-sented. The NURBS technique can retain the balance among the requirements for accuracy, surface continuity and data storage of geological structures. Finally, four alternative 3D modeling approaches are demonstrated with reference to some examples, which are selected according to the data quantity and accuracy specification. The proposed approaches offer flexible modeling patterns for different practical engineering demands.     

Digital body preservation: Technique and applications

High-fidelity anatomical models can be produced with three-dimensional (3D) scanning techniques and as such be digitally preserved, archived, and subsequently rendered through various media. Here, a novel methodology—digital body preservation—is presented for combining and matching scan geometry with radiographic imaging. The technique encompasses joining layers of 3D surface scans in an anatomical correct spatial relationship. To do so, a computed tomography (CT) volume is used as template to join and merge different surface scan geometries by means of nonrigid registration into a single environment. In addition, the use and applicability of the generated 3D models in digital learning modalities is presented. Finally, as computational expense is usually the main bottleneck in extended 3D applications, the influence of mesh simplification in combination with texture mapping on the quality of 3D models was investigated. The physical fidelity of the simplified meshes was evaluated in relation to their resolution and with respect to key anatomical features. Large- and medium-scale features were well preserved despite extensive 3D mesh simplification. Subtle fine-scale features, particular in curved areas demonstrated the major limitation to extensive mesh size reduction. Depending on the local topography, workable mesh sizes ranging from 10% to 3% of the original size could be obtained, making them usable in various learning applications and environments.     

实现ArcGIS环境下的确认性空间数据分析功能

在地理信息科学领域,空间分析扮演着中心的作用.但目前的地理信息系统商业软件中,空间分析功能仍是一个薄弱环节;即便是美国ESR I公司的ArcGIS,其空间分析模块也仅仅局限于探索性空间数据分析的功能,从而极大地限制了地理信息系统作为空间决策支持平台的作用.本研究的目标便是解决这一问题.我们经过反复实践实现了ArcGIS环境下的确认性空间数据分析功能,包括古典线性回归模型和空间计量经济学模型的标准诊断、估计、以及可靠性检测的复杂算法.通过对ArcGIS的二次开发,真正实现了地理信息系统和空间分析功能的全面集成.     

基于CityGML的数字城市快速建模研究

研究了基于CityGML的多层次细节3D城市模型快速建模方法,并将其结合到3DUGIS中用于数字城市建设。建模过程中考虑空间关系、拓扑关系和语义信息。建模过程自动化程度高,能够在三维空间直接进行空间分析,方便海量数据的交换与数据挖掘。并给出了上海世博园区三维信息系统结合具体应用案例。     

Take away body parts! An investigation into the use of 3D‐printed anatomical models in undergraduate anatomy education

Understanding the three‐dimensional (3D) nature of the human form is imperative for effective medical practice and the emergence of 3D printing creates numerous opportunities to enhance aspects of medical and healthcare training. A recently deceased, un‐embalmed donor was scanned through high‐resolution computed tomography. The scan data underwent segmentation and post‐processing and a range of 3D‐printed anatomical models were produced. A four‐stage mixed‐methods study was conducted to evaluate the educational value of the models in a medical program. (1) A quantitative pre/post‐test to assess change in learner knowledge following 3D‐printed model usage in a small group tutorial; (2) student focus group (3) a qualitative student questionnaire regarding personal student model usage (4) teaching faculty evaluation. The use of 3D‐printed models in small‐group anatomy teaching session resulted in a significant increase in knowledge (P = 0.0001) when compared to didactic 2D‐image based teaching methods. Student focus groups yielded six key themes regarding the use of 3D‐printed anatomical models: model properties, teaching integration, resource integration, assessment, clinical imaging, and pathology and anatomical variation. Questionnaires detailed how students used the models in the home environment and integrated them with anatomical learning resources such as textbooks and anatomy lectures. In conclusion, 3D‐printed anatomical models can be successfully produced from the CT data set of a recently deceased donor. These models can be used in anatomy education as a teaching tool in their own right, as well as a method for augmenting the curriculum and complementing established learning modalities, such as dissection‐based teaching. Anat Sci Educ 11: 44–53. © 2017 American Association of Anatomists.     

Geodatabase模型的版本控制原理及应用

介绍了GIS发展过程中出现的空间数据模型,以及不同空间数据模型的优缺点.对Geodatabase版本控制原理进行了分析说明,提出了使用版本控制来管理空间数据库的多用户并发操作、长事务处理,从而保证空间数据库的完整一致性.为建立和管理多用户的基于Geodatabase数据模型的空间数据库提供参考.     

高等教育E—learning工具评价的MTI三维模型

E—learning工具评价在高等教育领域具有广泛的应用。通过教学、管理、技术三维评价模型的构建,可以确定评价因素的集合,在此基础之上,综合运用层次分析法和模糊评价的方法,完成整个评价过程,实现定性与定量的结合,舳三维评价模型既能够系统、灵活地设置各评价因素,也使整个评价过程及其结果具有一定的科学性和合理性。     

Learning in Stereo: The Relationship Between Spatial Ability and 3D Digital Anatomy Models

Three-dimensional (3D) digital anatomical models show potential to demonstrate complex anatomical relationships; however, the literature is inconsistent as to whether they are effective in improving the anatomy performance, particularly for students with low spatial visualization ability (Vz). This study investigated the educational effectiveness of a 3D stereoscopic model of the pelvis, and the relationship between learning with 3D models and Vz. It was hypothesized that participants learning with a 3D pelvis model would outperform participants learning with a two-dimensional (2D) visualization or cadaveric specimen on a spatial anatomy test, particularly when comparing those with low Vz. Participants (n = 64) were stratified into three experimental groups, who each attended a learning session with either a 3D stereoscopic model (n = 21), 2D visualization (n = 21), or cadaveric specimen (n = 22) of the pelvis. Medical and pre-medical student participants completed a multiple-choice pre-test and post-test during their respective learning session, and a long-term retention (LTR) test 2 months later. Results showed no difference in anatomy test improvement or LTR performance between the experimental groups. A simple linear regression analysis showed that within the 3D group, participants with high Vz tended to retain more than those with low Vz on the LTR test (R² = 0.31, P = 0.01). The low Vz participants may be cognitively overloaded by the complex spatial cues from the 3D stereoscopic model. Results of this study should inform resource selection and curriculum design for health professional students, with attention to the impact of Vz on learning.     

基于Flash3D技术的小学立体几何教学平台的设计与实现

空间观念的培养是小学数学课程的重要目标之一。当前的教学过程中缺少可以操作的可视化学习工具,难以满足立体几何的教学需求,根据这一问题设计并实现了小学立体几何教学平台。文章阐述了该平台的设计理念、主要功能和系统架构,引进了新兴的Flash3D技术,并对著名的Flash3D引擎——Alternativa3D的开发流程进行了详细介绍,基于该引擎对平台进行实现。平台具有逼真的三维场景、丰富的感性资源、友好的交互方式等特点,是新技术在教学中应用的一次有益尝试。