Augmented reality and photogrammetry: A synergy to visualize physical and virtual city environments

Close-range photogrammetry is based on the acquisition of imagery to make accurate measurements and, eventually, three-dimensional (3D) photo-realistic models. These models are a photogrammetric product per se. They are usually integrated into virtual reality scenarios where additional data such as sound, text or video can be introduced, leading to multimedia virtual environments. These environments allow users both to navigate and interact on different platforms such as desktop PCs, laptops and small hand-held devices (mobile phones or PDAs). In very recent years, a new technology derived from virtual reality has emerged: Augmented Reality (AR), which is based on mixing real and virtual environments to boost human interactions and real-life navigations. The synergy of AR and photogrammetry opens up new possibilities in the field of 3D data visualization, navigation and interaction far beyond the traditional static navigation and interaction in front of a computer screen.In this paper we introduce a low-cost outdoor mobile AR application to integrate buildings of different urban spaces. High-accuracy 3D photo-models derived from close-range photogrammetry are integrated in real (physical) urban worlds. The augmented environment that is presented herein requires for visualization a see-through video head mounted display (HMD), whereas user’s movement navigation is achieved in the real world with the help of an inertial navigation sensor. After introducing the basics of AR technology, the paper will deal with real-time orientation and tracking in combined physical and virtual city environments, merging close-range photogrammetry and AR. There are, however, some software and complex issues, which are discussed in the paper.     

通用地图标绘系统的设计与实现

地图标绘指在地图背景上标绘各种具有空间特征的事、物的分布状态或行动部署,通用地图标绘系统指在计算机辅助下可实现在多种地图背景下标绘多种行业标号的信息系统。从分析用户需求入手,给出了该类系统的功能设置与界面风格、数据组织与关键算法等设计思想,详细阐述了具体的软件结构,软件实现方法与过程。     

全景景观地图的计算机辅助制作

针对全景景观地图制作过程复杂、效果差等问题,该文研究了全景景观地图计算机辅助制作的关键技术,包括渐进式投影的地形几何弯曲算法、地形高程垂直夸张、地物模型配置的滚落线生成算法等;完善了全景景观地图的机助制图过程和方法,提高了全景景观地图制图的效率,最后实现了全景景观地图制图原型系统。     

Computer-aided design of bus route maps

The bus route map is a diagram that aims to convey necessary information for map readers to find an appropriate way of moving from an origin to a destination. Design of bus route map is a complicated and time-consuming task that requires careful consideration of readability and aesthetics. This paper proposes a new computational method for designing bus route maps. The method helps us to reduce six types of undesirable elements in bus route maps, i.e., gap, shift, crossing, overlap, misalignment, and acute bend. The method consists of two phases: line layout phase determines the relative order of bus routes on each road segment and map layout phase calculates the actual position of bus routes drawn on a map. This paper applies the method to the design of bus route maps of Chiba City, Japan. The result supports the effectiveness of the method as well as reveals open topics for future research.     

The design and composition of persuasive maps

Persuasive maps are ubiquitous in society, yet cartographers have largely neglected to conduct serious, holistic research on them. Persuasive maps represent a form of visual communication that differs markedly from scientific geovisualization. First, many of these maps' communicative goals are anathema to those of scientific representation. Second, many persuasive maps ignore and defy established cartographic conventions. This article argues two things. First, the cartographic discipline can gain insight about how maps communicate information from the longitudinal and holistic analysis of persuasive maps. By comparing the differences and similarities of persuasive maps to scientific geovisualizations, researchers can begin to understand how persuasive maps communicate differently than scientific ones. Second, breaking persuasive maps down into composite parts may make it possible to identify persuasive map norms (i.e., methods of design that are embraced by producers of persuasive maps). The results of a content analysis of 256 persuasive maps are discussed. The article concludes that it may be possible to take the most statistically significant results from this study to begin identifying different rhetorical styles of persuasive maps.     

网络电子地图的设计与应用

目前GIS带动的产业急剧膨胀,已经深入到市政工程、企业决策、交通运输、公安急救、旅游、科研、教育等各个方面。非GIS专业用户对地图的需求是在基础底图的基础上加载本专业部门的定位与属性信息,这就要求GIS系统支持简单易用的电子地图系统,以便于为实现非GIS用户对GIS应用的需求。本文根据网络地图的特点和设计地图的影响因素,介绍了网络地图设计的理论,并以河南省人民政府网站电子地图为例,展示笔者对网络地图设计的认识。     

示意性轨道交通地图设计的研究

示意性地图作为一种特殊的专题地图,较之传统专题地图,有着不同的制图法则和制图方法,目前,示意性地图的设计还缺乏充足的理论依据和技术支持,本文从图面、风格、符号等方面对示意性地图的设计进行了研究,提出了一些示意性地图综合的方法,最后将这些方法应用到一个实例之中。     

On the design of formal theories of geographic space

This paper discusses the design of formal theories of geographic space for the application in Geographic Information Systems. GIS software is an implementation of formal theories of geographic space. The notions of formal theories are introduced and discussed in the context of examples from the GIS field.  Our approach is an application of the general framework of formal theories to the special class of theories of geographic space, in particular to the geometry of geographic space. A framework is introduced for characterizing and evaluating formal theories of geographic space and the process of their design. This is used to provide (1) a classification of formal theories of geographic space, (2) criteria of their adequacy, and (3) an evaluation of design decisions in the process of formalization.  The paper demonstrates the choices in the design of GIS and the dependencies between these choices. Considering the design space for theories underlying a GIS, we can see that current GIS are based on one choice: analytical geometry. Other designs are possible and a systematic exploration of alternative types of GIS, for example, based on constraints or based on stored spatial relations, becomes necessary. Received: 30 April 1997/Accepted: 8 March 1999     

Human genome behaviour: a powerful mechanism for optimizing the use of space technology in surveying networks design

An approach based on the behaviour of human genome is developed to efficiently provide a general framework for optimizing the use of space technology in surveying networks design. The developed approach attempts to apply the successful self-organizing principles based upon the biological evolution to artificial intelligence. It mimics the phenomena of natural selection observed in nature to achieve its goals by continuously adopting a population of candidate solutions and improving its performance over successive generations. The goal of adaptation is to find the best solution that optimizes the design of a surveying network based on the use of satellite observations. This network can be defined as a set of stations, co-ordinated by a series of sessions formed by placing receivers on the stations. The problem is to search for the best order for observing these sessions to give the best observation schedule at minimum cost. The obtained results prove the effectiveness of the developed technique in term of solution quality and computational efforts. The Corresponding Author in formed me that his address is likely to change soon. Please contact me, leick@spatial.maine.edu for the latest on this change.     

土地利用基础图件更新软件系统的设计与开发

土地利用基础图件是新一轮国土资源大调查中系列土地调查的基础。随着我国经济建设飞速发展,土地利用状况发生了巨大变化,如何快速、准确地更新土地利用基础图件已成为亟待解决的重要问题。本文阐述了土地利用基础图件更新软件系统的需求、特点、系统功能和实现方法。该软件系统将整个图件更新作业流程一体化,实现了GPS、RS、GIS技术集成支持下的土地利用基础图件的快速更新。     

Augmented virtual environment: fusion of real-time video and 3D models in the digital earth system

ABSTRACT

An Augmented virtual environment (AVE) is concerned with the fusion of real-time video with 3D models or scenes so as to augment the virtual environment. In this paper, a new approach to establish an AVE with a wide field of view is proposed, including real-time video projection, multiple video texture fusion and 3D visualization of moving objects. A new diagonally weighted algorithm is proposed to smooth the apparent gaps within the overlapping area between the two adjacent videos. A visualization method for the location and trajectory of a moving virtual object is proposed to display the moving object and its trajectory in the 3D virtual environment. The experimental results showed that the proposed set of algorithms are able to fuse multiple real-time videos with 3D models efficiently, and the experiment runs a 3D scene containing two million triangles and six real-time videos at around 55 frames per second on a laptop with 1GB of graphics card memory. In addition, a realistic AVE with a wide field of view was created based on the Digital Earth Science Platform by fusing three videos with a complex indoor virtual scene, visualizing a moving object and drawing its trajectory in the real time.     

专题地图设计辅助案例库建设的若干问题

地图制图案例是地图制图经验与知识组织与管理的基本单元。专题地图设计辅助案例库建设旨在构建一个独立于制图人员的地图制图经验与知识持续积累、有效融合与便捷再应用的系统与方法。文章立足于地图生产的现实需求,从工程化视角介绍了地图设计辅助案例库建设的研究内容与基本思路,重点对专题制图案例模板的内容设计进行了论述。地图制图案例库建设与应用为实践中地图设计水平与地图生产效率的持续提高提供了有效的支持。     

SBAS-derived TEC maps: a new tool to forecast the spatial maps of maximum probable scintillation index over India

With the increase in the use of satellite-based navigation services, the forecasting of L band scintillation has turned out to be of paramount importance as it affects their accuracy and availability. Forecasting the time of occurrence or non-occurrence, strength and probable location of scintillation enables the service providers and users to take appropriate action to mitigate the effects and optimize the services. We use the recently developed method to retrieve TEC from the ionospheric correction data transmitted by the Indian satellite-based augmentation system (SBAS)–GAGAN. By making use of the established linear relation between the dusk time TEC and the maximum probable scintillation intensity (S_4max), scintillation forecast maps have been generated as early as 1930 LT. The superposition of actual S₄ measurements, obtained from the GAGAN network of receivers, on the forecasted S_4max map shows that the actual measurements are less than the predicted S_4max except on very few occasions. The potential of the simple technique to predict the 2 D maps of maximum probable scintillation index for the whole night has been demonstrated which with more refinements could evolve into a viable forecast or forewarning system.     

应用遥控直升机进行大比例尺地形测绘试验研究

采用遥控模型直升机作为航空摄影平台,无线数字摄像头摄影,按近景摄影测量方式进行处理,测绘目标区域小面积大比例尺地形图,作者将此方式称之为数字近景航空摄影测量。通过对面积为1.3km2的试验区域进行数字近景航空摄影测量,并与常规数字化测图成果进行对比分析。结果证明,采用近景航空摄影测量方法测绘小面积大比例尺地形图,其精度可满足摄影测量精度要求,并可提供数字正射影像图,同时减少测图成本。     

GPS运行轨道仿真系统的设计与开发

为了进行航天器系统仿真技术研究,本文提出了应用虚拟现实技术开发GPS运行轨道仿真系统框架体系:利用Matlab仿真,得到并验证了通过对SP3星历数据处理构建正确三维仿真运行轨道的方法;完成了实时交互的三维可视化仿真系统主要功能的实现;最终取得了良好的仿真效果,有利于GPS用户系统的设计与监控.     

Exploring the effectiveness of location‐based social media in modeling user activity space: A case study of Weibo

Location‐based social media (LBSM) has been widely utilized to supplement traditional survey methods in modeling human activity patterns. However, there has not been sufficient study to assess the reliability of these data in deriving human movement. This research aims to evaluate how data collection duration and sample sizes affect the reliability of LBSM data in activity modeling based on two indicators: radius of gyration (ROG) and entropy. We use a linear regression model with logarithmic transformation to approximate how the magnitude of each indicator changes with different data collection durations—from 1 to 12 months. The results indicate that both ROG and entropy increase when the amount of data increases. However, the rate of increase slows down and approaches zero eventually. We also approximated the limit values and verified that with 12‐month data, we are at approximately >95% magnitude of the limit values for both indicators in all three cities. The clustering analysis also demonstrated that there are outlier users who exhibit distinct patterns. This case study focuses on three Chinese cities (Beijing, Shanghai, and Guangzhou) and provides a useful reference to explore the balance point between data effectiveness and an appropriate sample size from LBSM data.     

1:50 000基础地理数据库存储系统设计

本文结合国家基础地理信息中心1:50000基础地理数据库建库的需求和数据特点,通过分析数据存储技术发展趋势,给出了较为详尽可行的数据存储系统设计方案,并论述了上述软硬件平台的实际应用。     

Exploring differences of visual attention in pedestrian navigation when using 2D maps and 3D geo-browsers

ABSTRACT

Despite the now-ubiquitous two-dimensional (2D) electronic maps, three-dimensional (3D) globe viewers, or 3D geo-browsers such as Google Earth and NASA World Wind have gained much attention. However, the effect of such interactive 3D geo-browsers on spatial knowledge acquisition and decision-making is not well known. This study aims to explore the potential benefits of using interactive 3D geo-browsers in three processes of pedestrian navigation (self-localization, spatial knowledge acquisition, and decision-making) in digital environments. We employed eye tracking to show differences of visual attention in pedestrian navigation between a 2D map (Google Map) and a 3D geo-browser (Google Earth). The results indicated that benefits and drawbacks of 3D representations are task dependent. Participants using the 3D geo-browser had an extensively visual search resulting in significantly longer response time than the 2D participants for spatial knowledge acquisition, whereas 3D users performed a more efficient visual search and resulted in a better navigation performance at complex decision points. We speculate that the inefficient knowledge acquisition when using the 3D geo-browser was most probably due to information overload and obstructed views. Landmarks in photorealistic 3D models assisted recall of spatial knowledge from mental maps, which contributed to efficient decision-making at a complex turning point. These empirical results can be helpful to improve the usability of pedestrian navigation systems.     

The design and the development of a hyperspectral and multispectral airborne mapping system

Flexible and cost-effective tools for rapid image acquisition and natural resource mapping are needed by land managers. This paper describes the hardware and software architecture of a low-cost system that can be deployed on a light aircraft for rapid data acquisition. The Hyperspectral and Multispectral Cameras for Airborne Mapping (HAMCAM) was designed and developed in the Geospatial Laboratory for Environmental Dynamics at the University of Idaho as a student-learning tool, and to enhance the existing curriculum currently offered. The system integrates a hyperspectral sensor with four multispectral cameras, an Inertial Navigation System (INS), a Wide Area Augmentation System (WAAS)-capable Global Positioning System (GPS), a data acquisition computer, and custom software for running the sensors in a variety of different modes. The outputs include very high resolution imagery obtained in four adjustable visible and near-infrared bands from the multispectral imager. The hyperspectral sensor acquires 240 spectral bands along 2.7 nm intervals within the 445–900 nm range. The INS provides aircraft pitch, roll and yaw information for rapid geo-registration of the imagery. This paper will discuss the challenges associated with the development of the system and the integration of components and software for implementation of this system for natural resource management applications. In addition, sample imagery acquired by the sensor will be presented.