Map Design Evaluation for Mobile Display

How to effectively represent spatial information on handheld mobile devices is a key question, given the increasing use of personal digital assistants (PDAs) and cell phones concurrent with the development of location-based services. The mobile use of digital maps on small displays presents new capabilities and challenges that differ from using paper maps in a mobile setting or viewing digital maps on a desktop computer. This research addresses these issues through a study that evaluated maps on a mobile device used for a field-based navigation task. Map representations at two levels of generalization were compared by analyzing subject performance in a pedestrian route-following task, in which a handheld computer was used as a navigation aid. Subject time and accuracy as well as interaction with the mobile device during the task were measured. The results carry implications for map design for small, mobile displays and identify factors that affect the use of maps while moving. Maps are and will increasingly be used on small displays in mobile contexts for a variety of purposes and in many different environments. The requirements and preferences of mobile users, as well as how these maps are used in different contexts, must be understood in order to inform more effective designs.     

Geospatial Information Visualization User Interface Issues

User interfaces for geospatial information are the tools by which users interact with and explore that information. The provision of appropriate interface tools for exploiting the potential of contemporary geospatial visualization products is essential if they are to be used efficiently and effectively. This paper addresses issues and challenges in interface development and usage that are identified as paramount within the geospatial visualization community.     

Effectiveness and Efficiency of Map Symbols for Dynamic Geographic Information Visualization

The quality of dynamic map symbols plays an important role in the representation of spatial-temporal changes. This paper reports an investigation into the quality of dynamic symbols. To assess the quality of such symbols, a set of traffic flow data is used for the production of different kinds of dynamic maps, with focus on four variables, i.e. size, color, frame rate and display format. Two quantitative measures are used for analysis, i.e. deviation and response time. A set of traffic data is used for the production of dynamic maps for evaluation. The experimental results show that the size is more efficient and more effective than color for dynamic maps with the same frame rate and display format. The most efficient and effective color class number is 10 on the large format display such as 1024 × 768 pixels. And the most efficient and effective size class number is 15 on large format display such as 1024 × 768 pixels. The effective frame rate for dynamic map animation is smaller than that of the general animation on the Internet or Quick Time and AVI format video. The most efficient and most effective frame rate is 3 frames per second in the color expression and 6 frames per second in the size expression. In sum, the effective and efficient value of color, size and frame rate on large format display is less than the value on the small format display. These results suggest the frame rate should be reduced on the small format display. It is hoped that the results from this study will be of help in the design of effective and efficient dynamic map symbols for geographical information visualization.     

对地理空间信息图形符号显示标准化的探讨

地理空间信息的图形符号显示标准化是地理空间数据规范化的重要组成,也是其走向数字化、网络化和移动化的必备条件,以确保地理空间信息在感知和认知上的一致、有效和准确,提高其通用性使之能在更广泛领域中沟通和共享。本文通过参照有关国际国家标准和对大量相关文献的调研,对符号分类体系、显示介质、视觉感知、视觉变量、分级表达、颜色标准等方面进行了探讨,以期对地理空间信息图形符号的显示标准的制定提供一定参考或借鉴。     

Integrating Indoor and Outdoor Spaces for Pedestrian Navigation Guidance: A Review

In light of the many improvements within 3D urban modeling and Location‐Based Services, this article provides a timely review of the state‐of‐the‐art on integrating indoor and outdoor spaces in pedestrian navigation guidance aids. With people moving seamlessly between buildings and surrounding areas, navigation guidance tools should extend from merely outdoor or indoor guidance, to provide support in the combined indoor‐outdoor context. This article first examines the challenges and complexities of integrating indoor and outdoor spaces into a single navigation system. Next, by using objective selection criteria, 36 relevant studies were withheld and further reviewed on their specific developments in data model requirements, and algorithmic and context support for integrated IO navigation systems. This review shows that the challenges of dealing with both indoor and outdoor space structures, while taking into account pedestrian's freer use of space, currently complicate the proposition of a unified IO space concept for navigation. However, there are some ongoing developments (e.g. context definitions, algorithmic extensions, increased data availability, growing awareness of pedestrians’ perception during wayfinding) that will help to bring outdoor and indoor spaces closer together in the realm of combined geospatial analysis.     

星载激光光斑影像激光指向变化探测法

地面光斑足印的定位精度高度依赖于激光指向角的测量精度,星载激光光斑质心提取及其变化规律对激光指向角的分析具有重要的意义。本文基于ICESat/GLAS的激光剖面阵列（laser profile array,LPA）影像数据,首先利用灰度一阶矩阵法提取LPA的质心,精度优于0.3个像素,LPA相对定位精度优于0.11个像素。其次利用傅里叶变换和傅里叶级数拟合对LPA质心坐标的变化进行周期探测和建模分析,结果表明,激光光斑影像的质心坐标存在1.83×10^-4 Hz、3.36×10^-4 Hz、5.19×10^-4 Hz和6.71×10^-4 Hz 4个明显的周期变化,拟合结果的相关性R²达到了0.86,拟合精度可达0.4″,优于0.13个像素,得到了较好的结果。可为我国的高分七号和后续的卫星激光测高数据处理提供参考。     

Geospatial multiple logistic regression approach for habitat characterization of scarce plant population: A case study of <Emphasis Type="Italic">Pittosporum eriocarpum</Emphasis> Royle (an endemic species of Uttarakhand,India)

Increasing concern for biodiversity conservation at species level resulted in the development of cost effective tools for getting information at larger scale. Modeling distribution of species using remote sensing and geographic information has already proved its potentials to get such information with less effort. Pittosporum eriocarpum Royle is an endemic and threatened tree species of Uttarakhand, yet till now its regional distribution is poorly known. This study using geospatial modelling tools indentified several localities of potential occurrence of this species in the Mussoorie hills and Doon valley, and also provides information on its habitat specificity. The main objective of the study is to predict the suitable habitats for endangered plant species in Himalayan region using logistic regression model where availability of sufficient data on species presenceabsence is a major limitation for larger areas.     

A Simplified Semi-Automatic Technique for Highway Extraction from High-Resolution Airborne LiDAR Data and Orthophotos

Information on highways is an essential input for various geospatial applications, including car navigation, forensic analysis on highway geometries, and intelligent transportation systems. Semi-automatic and automatic extractions of highways are critical for the regular updating of municipal databases and for highway maintenance. This study presents a semi-automatic data processing approach for extracting highways from high-resolution airborne LiDAR height information and aerial orthophotos. The method was developed based on two data sets. Experimental results for the first testing site showed that the accuracy of the proposed method for highway extraction was 74.50 % for completeness and 73.13 % for correctness. Meanwhile, the completeness and correctness for the second testing site were 71.20 and 70.72 %, respectively. The proposed method was compared with an object-based approach on a different data set. The accuracy for highway extraction of the object-based approach was 64.29 % for completeness and 63.11 % for correctness, whereas that of the proposed method was 67.14 % for completeness and 65.08 % for correctness. This research aims to promote semi-automatic highway extraction from LiDAR data and orthophotos by proposing a new approach and a multistep post-processing technique. The proposed method provides an accurate final output that is valuable for a wide range of geospatial applications.     

Parallel computing solutions for Markov chain spatial sequential simulation of categorical fields

The Markov chain random field (MCRF) model is a spatial statistical approach for modeling categorical spatial variables in multiple dimensions. However, this approach tends to be computationally costly when dealing with large data sets because of its sequential simulation processes. Therefore, improving its computational efficiency is necessary in order to run this model on larger sizes of spatial data. In this study, we suggested four parallel computing solutions by using both central processing unit (CPU) and graphics processing unit (GPU) for executing the sequential simulation algorithm of the MCRF model, and compared them with the nonparallel computing solution on computation time spent for a land cover post-classification. The four parallel computing solutions are: (1) multicore processor parallel computing (MP), (2) parallel computing by GPU-accelerated nearest neighbor searching (GNNS), (3) MP with GPU-accelerated nearest neighbor searching (MP-GNNS), and (4) parallel computing by GPU-accelerated approximation and GPU-accelerated nearest neighbor searching (GA-GNNS). Experimental results indicated that all of the four parallel computing solutions are at least 1.8× faster than the nonparallel solution. Particularly, the GA-GNNS solution with 512 threads per block is around 83× faster than the nonparallel solution when conducting a land cover post-classification with a remotely sensed image of 1000?×?1000 pixels.     

Exploring Real‐Time Geoprocessing in Cloud Computing: Navigation Services Case Study

Today, many real‐time geospatial applications (e.g. navigation and location‐based services) involve data‐ and/or compute‐intensive geoprocessing tasks where performance is of great importance. Cloud computing, a promising platform with a large pool of storage and computing resources, could be a practical solution for hosting vast amounts of data and for real‐time processing. In this article, we explored the feasibility of using Google App Engine (GAE), the cloud computing technology by Google, for a module in navigation services, called Integrated GNSS (iGNSS) QoS prediction. The objective of this module is to predict quality of iGNSS positioning solutions for prospective routes in advance. iGNSS QoS prediction involves the real‐time computation of large Triangulated Irregular Networks (TINs) generated from LiDAR data. We experimented with the Google App Engine (GAE) and stored a large TIN for two geoprocessing operations (proximity and bounding box) required for iGNSS QoS prediction. The experimental results revealed that while cloud computing can potentially be used for development and deployment of data‐ and/or compute‐intensive geospatial applications, current cloud platforms require improvements and special tools for handling real‐time geoprocessing, such as iGNSS QoS prediction, efficiently. The article also provides a set of general guidelines for future development of real‐time geoprocessing in clouds.     

Representation and its Relationship with Cartographic Visualization

A research agenda is presented which addresses the current role and potential of map displays. By considering the geospatial data used in visualization, the form and design of maps, the purposes for which map displays are created, the nature of the map user community, and the technology employed to visualize geospatial data, a thorough overview of the nature of cartographic visualization is given. Under the same themes, and sourced in cartographic tradition, cartographic practice and technological opportunities, a series of possible research avenues are highlighted. The important links between representation and the user interface, map user cognition and the geospatial database are stressed.     

基于ArcEngine电子海图显示技术与实现

电子海图在当前海洋导航定位中的作用越来越大。本文重点研究电子海图显示过程中涉及到的相关技术,利用GIS ArcEngine技术实现Shapefile格式电子海图的读取与显示,按照S-52国际标准完成对电子海图渲染,利用墨卡托投影将平面坐标转换为地理坐标实现电子海图精确定位,将电子海图Shapefile属性数据转换为GeoDatabase提高电子海图显示速度。电子海图显示效果与功能表明,本研究具有较高实用价值和应用前景。     

Pre-processing considerations of IRS-P6 LISS-4 imagery

Wide image swath with a high geometric resolution is required for photogrammetric applications. Both demands can be satisfied using staggered line arrays. Different bands of IRS-P6 LISS-4 sensor use staggered arrays for imaging. This paper describes a method for computing the offset for geometric alignment of odd and even lines of the staggered array of IRS-P6 LISS-4 imagery. The odd and even pixel rows are separated by 35 μm (equal to 5 pixels) in the focal plane in the along-track direction. Slightly different viewing angles of both lines of a staggered array can result in a variable sampling pattern on the ground because of the attitude fluctuations, satellite movement, terrain topography, PSM steering and small variations in the angular placement of the CCD lines (from the pre-launch values) in the focal plane. Non-accounting of this variable sampling value during the video data alignment will introduce deterioration of image quality and geometric discontinuity of features. The stagger parameters can be computed by the reconstruction of the viewing geometry with a calibrated camera geometry model and a public domain DEM. The impact of the line separation in the focal plane during imaging for different viewing configurations and terrain heights are studied and reported in this paper. Computed values from the model are in good agreement with what is observed in the raw image for different view angles. The results verify the model and are representative of the stability of the platform.     

地理空间可视分析及其研究方向综述

介绍了可视分析的概念和内涵,分析了可视分析与可视化、地理空间可视分析等概念的关系。研究了地理空间可视分析的概念和内涵,在此基础上提出了地理空间可视分析的5个重要研究方向:面向可视分析的地理空间数据转换;多维地理空间数据的深层可视化表达和分析;地理空间可视分析推理;地理空间数据的协同可视分析和决策;地理空间数据可视分析工具的设计和评估。     

Developing interactive geospatial holograms for spatial decision-making

Spatial decision-making in time-critical situations requires effective and usable two-dimensional and three-dimensional (3D) cartographic products. Holographic displays allow decision makers to work with auto-stereoscopic maps without the hassle of interacting with complex user interfaces or additional vision hardware. Holographic production processes have advanced greatly in a short period and now support timely and full integration of digital 3D models in geospatial holograms. George Mason University’s and Zebra Imaging’s research on interactive holographic motion displays showcases the leadership in moving cartography and geovisualization research in the US forward. In close cooperation with academic researchers, decision makers, and domain experts, the usability and usefulness of these cartographic products is tested and design guidelines for effective geospatial holograms are being developed.     

Harnessing the power of immersive virtual reality - visualization and analysis of 3D earth science data sets

ABSTRACT

The availability and quantity of remotely sensed and terrestrial geospatial data sets are on the rise. Historically, these data sets have been analyzed and quarried on 2D desktop computers; however, immersive technologies and specifically immersive virtual reality (iVR) allow for the integration, visualization, analysis, and exploration of these 3D geospatial data sets. iVR can deliver remote and large-scale geospatial data sets to the laboratory, providing embodied experiences of field sites across the earth and beyond. We describe a workflow for the ingestion of geospatial data sets and the development of an iVR workbench, and present the application of these for an experience of Iceland’s Thrihnukar volcano where we: (1) combined satellite imagery with terrain elevation data to create a basic reconstruction of the physical site; (2) used terrestrial LiDAR data to provide a geo-referenced point cloud model of the magmatic-volcanic system, as well as the LiDAR intensity values for the identification of rock types; and (3) used Structure-from-Motion (SfM) to construct a photorealistic point cloud of the inside volcano. The workbench provides tools for the direct manipulation of the georeferenced data sets, including scaling, rotation, and translation, and a suite of geometric measurement tools, including length, area, and volume. Future developments will be inspired by an ongoing user study that formally evaluates the workbench’s mature components in the context of fieldwork and analyses activities.     

基于开放互操作标准的分布式地理空间模型共享研究

传统的单机环境和封闭式网络环境由于有限的资源利用能力, 难以充分支持分散地学数据、模型等资源的共享与应用集成。基于网络环境的信息交换特点, 提出了分布式地理空间模型共享的服务体系。该体系以数据、模型、元数据等互操作要素为核心, 通过网络将数据、模型等网络节点进行开放式耦合。针对地理空间模型服务的互操作问题, 提出了分布式环境下的模型共享服务交互接口, 该接口定义了模型服务元数据、模型服务的交互操作、模型服务的通讯方式等交互规则, 尽可能地降低模型服务与模型终端之间在数据交换、功能调用等方面的互操作困难。为了降低将模型共享为模型服务的实现难度, 设计和开发了地理空间模型共享平台, 并介绍了在该平台上发布地理空间模型的2种方法。最后介绍了研究成果在Prairie生态模型共享方面的应用实践。     

从测绘学到地球空间信息智能服务科学

回顾了从传统测绘学到当今地球空间信息智能服务科学的60年发展历程;总结了测绘学从模拟到解析再到数字化发展的3个重要阶段;介绍了GNSS、RS与GIS(3S)集成,从而形成了地球空间信息学的兴起;分析了数字地球时代地球空间信息学的发展,进而论述了当今智慧地球时代地球空间信息科学走向实时智能服务的最新进展,并对"互联网+"空间信息智能服务的3个发展水平进行了重点论述。可以肯定,在大数据时代传统的测绘学必将集通信、导航、遥感、人工智能、虚拟现实和脑认知科学之大成,发展成为地球空间信息智能服务科学,为富国强军与利民作出应有的贡献。     

Spatio-temporal evaluation matrices for geospatial data

The global geospatial community is investing substantial effort in providing tools for geospatial data-quality information analysis and systematizing the criteria for geospatial data quality. The importance of these activities is increasing, especially in the last decade, which has witnessed an enormous expansion of geospatial data use in general and especially among mass users. Although geospatial data producers are striving to define and present data-quality standards to users and users increasingly need to assess the fitness for use of the data, the success of these activities is still far from what is expected or required. As a consequence, neglect or misunderstanding of data quality among users results in misuse or risks. This paper presents an aid in spatio-temporal quality evaluation through the use of spatio-temporal evaluation matrices (STEM) and the index of spatio-temporal anticipations (INSTANT) matrices. With the help of these two simple tools, geospatial data producers can systematically categorize and visualize the granularity of their spatio-temporal data, and users can present their requirements in the same way using business intelligence principles and a Web 2.0 approach. The basic principles and some examples are presented in the paper, and potential further applied research activities are briefly described.