How to Enhance Cartographic Visualisations of Natural Hazards Assessment Results

Abstract

Cartographic visualisations are important tools for the communication of hazard related data among stakeholders. Although these representations are essential for various hazard management tasks, an analysis of existing hazard visualisations showed that they often disregard cartographic principles. This leads to confusion on the part of users through poor representations and consequently to an impairment of the information flow. The objective of this research is to offer suggestions for enhanced hazard visualisations to facilitate hazard management tasks and decision making. Existing cartographic shortcomings are identified based on an extensive analysis of hazard visualisations and an expert survey. These shortcomings are discussed and improvements for important cartographic elements are presented.     

Cartograms for Use in Forecasting Weather-Driven Natural Hazards

This paper evaluates the potential of using cartograms for visualizing and interpreting forecasts of weather-driven natural hazards in the context of global weather forecasting and early warning systems. The use of cartograms is intended to supplement traditional cartographic representations of the hazards in order to highlight the severity of an upcoming event. Cartogrammetric transformations are applied to forecasts of floods, heatwaves, windstorms and snowstorms taken from the European Centre for Medium-range Weather Forecasts (ECMWF) forecast archive. Key cartogram design principles in standard weather forecast visualization are tested. Optimal cartogram transformation is found to be dependent on geographical features (such as coastlines) and forecast features (such as snowstorm intensity). For highly spatially autocorrelated weather variables used in analysing several upcoming natural hazards such as 2m temperature anomaly, the visualization of the distortion provides a promising addition to standard forecast visualizations for highlighting upcoming weather-driven natural hazards.     

Accuracy assessment of the global forest watch tree cover 2000 in China

Inaccurate information on forest resources could hamper forest conservation, reforestation and sustainable management. Remote-sensing products have emerged as key tools in forest cover monitoring. The Global Forest Watch (GFW) dataset as an interactive remote sensing product, is now applied by more than 2 million users including researchers, conservationists and local communities for analyzing forest cover changes. The quality of this product varies spatially, and local validations are recommended before using the data for inventory and management tasks. Our study evaluated the accuracy and suitability of the GFW dataset for analyzing China’s forest cover. We conducted a validation based on a streamlined visual interpretation procedure using high-resolution optical imagery on Google Earth to map the uncertainties and inaccuracies of GFW Tree Cover 2000 in China. We then estimated China’s forest area after considering the data uncertainty, made a comparison with the data reported by the National Forest Inventory of China (CNFI) to understand where and how the land-based inventory differs from the presence/absence-based remote sensing data. The results showed that the overall accuracy of the GFW Tree Cover 2000 data reached 94.5 %. The user’s and producer’s accuracy of forest classification was 89.26 % and 82.13 %. The sample-based area estimation using GFW showed a larger forest area than the figure reported by CNFI in mainland China, while data discrepancy varied at provincial levels. The study provides a detailed performance assessment of GFW in terms of accuracy of defining forest, and we advise the consideration of data uncertainty in forest cover estimates for future forest management.     

省级地图数据库应急保障制图体系探索与建设

介绍了省级地图数据库应急保障体系的总体架构,以及体系的建设内容和示范应用子系统功能。进行省级地图数据库应急保障制图体系的探索与建设,可将基础地图信息数据和专题图数据集中管理,并具有全面的数据采集更新、数据编辑处理、数据入库管理、应急地图产品的快速定制及出版印刷等功能,为地图制图的信息化建设奠定基础,并推进应急保障制图快速化服务进程。     

Web-based 4D visualization of marine geo-data using WebGL

For marine logistics and maintenance of extensive and expensive marine engineering projects in the coastal zone, it is essential that institutions provide the public with relevant information in an easily understandable yet comprehensive manner over the web. A perennial challenge, however, has been the development of spatio-temporal (four-dimensional (4D)) geo-visualization algorithms to enable the integration of time-varying geo-information in map-based visualizations on the Internet. In this paper, we address the challenge of visualizing marine spatial data in web-based applications through a 4D visualization concept, focusing on usability criteria, performance parameters, the required implementation effort, and delivering a breath of spatial information that supports decision-making on multiple levels. We used Web Graphic Library (WebGL) to validate our concept through a prototypical implementation. In our technology evaluation, WebGL proved highly suitable for the development of interactive, responsive, efficient, and mobile web-based Geographic Information applications, including 2D, 3D, and 4D (spatiotemporal) content. During our research, we identified a number of open research questions, including mapping graphic variables to thematic expressivity, representation of the time dimension in 4D systems, generic temporal generalization, and integration of (pseudo-)photorealistic illustrations in web-based geo-visualization systems.     

“高分二号”卫星在黄土地质灾害解译中的应用研究

黄土高原地区地质灾害多发频发,危害严重,应用亚米级的高分二号(GF-2)卫星影像数据,提取地质灾害信息,并对室内解译结果进行了野外查证。本文提出了以GF-2卫星数据为主要信息源,进行地质灾害解译的技术方案;并以宁夏南部黄土高原区为例,验证了该方法的适用性,为规模化地开展基于国产高分系列卫星的黄土高原地区地质灾害遥感解译提供了可行的技术方案;通过GF-2卫星影像与常用的国内外卫星数据用于地质灾害信息判释的对比研究,认为GF-2卫星影像对于地质灾害信息的识别能够满足地质灾害遥感解译的要求,GF-2卫星影像的应用具有较高的性价比和显著的经济社会效益。     

Teaching Mapping for Digital Natives: New Pedagogical Ideas for Undergraduate Cartography Education

The current generation of US students engaging with cartography has always had some form of access to computing technologies. Further, this generation has always known a world with networked computer capabilities – the Internet and World Wide Web. Their experience of cartography is largely through fleeting representations shown on a variety of display screens, thereby encountering information differently than most of their instructors. Teaching cartography to these “digital natives” consequently challenges teachers to engage increasing levels of experience and knowledge of technology while assuring fundamental understanding of cartographic concepts and analysis techniques.

Although GIS is used in a vast range of fields, we believe many students are discouraged from programs and courses oriented towards educating cartographic specialists. However, general interest in mapping has never been as significant a part of American culture as it is today. In spite of accessible modes of digital mapping now widely available, introducing cartographic fundamentals retains great significance for undergraduate cartography education. In this paper we present a new pedagogical model for undergraduate cartography education that introduces students finding curiousity in mapping, but lacking desire to become cartographic specialists, to mapping. This model enables undergraduate students to learn fundamentals and begin to reflect critically on the concepts and techniques of modern cartography. Our example stems from a class that systematically addresses barriers to learning and mapping through active-learning based approaches in an interactive classroom. The active-learning approach involves significant engagements with the potentials and challenges of modern cartography in the information age by embracing inquiry-based pedagogical methods and learning with and about mapping.     

Spatial Prediction of Landslide Hazard Using Fuzzy k-means and Dempster-Shafer Theory

Landslide databases and input parameters used for modeling landslide hazard often contain imprecisions and uncertainties inherent in the decision‐making process. Dealing with imprecision and uncertainty requires techniques that go beyond classical logic. In this paper, methods of fuzzy k‐means classification were used to assign digital terrain attributes to continuous landform classes whereas the Dempster‐Shafer theory of evidence was used to represent and manage imprecise information and to deal with uncertainties. The paper introduces the integration of the fuzzy k‐means classification method and the Dempster‐Shafer theory of evidence to model landslide hazard in roaded and roadless areas illustrated through a case study in the Clearwater National Forest in central Idaho, USA. Sample probabilistic maps of landslide hazard potential and uncertainties are presented. The probabilistic maps are intended to help decision‐making in effective forest management and planning.     

From taxonomies to ontologies: formalizing generalization knowledge for on-demand mapping

Automation of the cartographic design process is central to the delivery of bespoke maps via the web. In this paper, ontological modeling is used to explicitly represent and articulate the knowledge used in this decision-making process. A use case focuses on the visualization of road traffic accident data as a way of illustrating how ontologies provide a framework by which salient and contextual information can be integrated in a meaningful manner. Such systems are in anticipation of web-based services in which the user knows what they need, but do not have the cartographic ability to get what they want.     

Cartography-Oriented Design of 3D Geospatial Information Visualization – Overview and Techniques

In economy, society and personal life map-based interactive geospatial visualization becomes a natural element of a growing number of applications and systems. The visualization of 3D geospatial information, however, raises the question how to represent the information in an effective way. Considerable research has been done in technology-driven directions in the fields of cartography and computer graphics (e.g., design principles, visualization techniques). Here, non-photorealistic rendering (NPR) represents a promising visualization category – situated between both fields – that offers a large number of degrees for the cartography-oriented visual design of complex 2D and 3D geospatial information for a given application context. Still today, however, specifications and techniques for mapping cartographic design principles to the state-of-the-art rendering pipeline of 3D computer graphics remain to be explored. This paper revisits cartographic design principles for 3D geospatial visualization and introduces an extended 3D semiotic model that complies with the general, interactive visualization pipeline. Based on this model, we propose NPR techniques to interactively synthesize cartographic renditions of basic feature types, such as terrain, water, and buildings. In particular, it includes a novel iconification concept to seamlessly interpolate between photorealistic and cartographic representations of 3D landmarks. Our work concludes with a discussion of open challenges in this field of research, including topics, such as user interaction and evaluation.     

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.     

A framework for teaching the timeless way of mapmaking

There are now many opportunities to learn how to make maps through technical training with mapmaking tools, including geographic information systems and web-based mapping services. In cartographic education, two challenges with teaching through practice stem from the disruptive nature of mapmaking tools and the tradition of teaching cartographic principles by rule or convention. This article outlines a framework for a pattern language to organize and share practical information about principles for making maps. The article provides an example pattern for mapmaking and discusses how this framework addresses recurring problems with teaching through practice.     

Developing a Virtual Reality User Interface (VRUI) for Geographic Information Retrieval on the Internet

The exponential growth of the World Wide Web provides the potential for greatly enhanced dissemination of global data-sets and information. However, the concurrent rise in data supply also means that new tools are required for information retrieval beyond the conventional graphical user-interface (GUI). This paper reviews the development of web-based GIS functionality and demonstrates how the multi-dimensional capabilities of VR tools can bring enhanced data exploration and visualisation onto the Internet by providing a more powerful 3D user-interface to identify and query data-sets. One key to the development of such interactive tools is the link between the Virtual Reality Modelling Language (VRML) and the JAVA platform, which together allow dynamic 3D content to be accessed through a web browser. Exploration of large diverse data-sets is demonstrated by a prototype system allowing the integration of terrain-based geoscience data-sets for scientific visualisation and education. The current limitations of the technology are discussed and further suggestions are made to improve the information content of the Internet.     

Multivariate Analysis and Geovisualization with an Integrated Geographic Knowledge Discovery Approach

The discovery, interpretation, and presentation of multivariate spatial patterns are important for scientific understanding of complex geographic problems. This research integrates computational, visual, and cartographic methods together to detect and visualize multivariate spatial patterns. The integrated approach is able to: (1) perform multivariate analysis, dimensional reduction, and data reduction (summarizing a large number of input data items in a moderate number of clusters) with the Self-Organizing Map (SOM); (2) encode the SOM result with a systematically designed color scheme; (3) visualize the multivariate patterns with a modified Parallel Coordinate Plot (PCP) display and a geographic map (GeoMap); and (4) support human interactions to explore and examine patterns. The research shows that such "mixed initiative" methods (computational and visual) can mitigate each other's weakness and collaboratively discover complex patterns in large geographic datasets, in an effective and efficient way.     

An estimate of the geodetic accuracy attainable with a transportable lunar laser station

A transportable lunar laser ranging station can be expected to measure the range to the lunar corner retroreflectors from a site on the Earth's surface with an uncertainty of about 3 cms. The accuracy with which that station can infer its geocentric position is influenced by many factors including the uncertainties in the pole position and rotation rate of the Earth and the data loss due to weather. The results of a simplified modelling study intended to include these factors are presented in cartographic form. The modelling indicates that, assuming the successful operation of three or more widely separated fixed laser stations, the transportable station will be able to determine its relative geocentric position in all three coordinates with an accuracy comparable to the original range uncertainty.     

Hypercube-Based Visualization Architecture for Web-Based Environmental Geospatial Information Systems

The geospatial field significantly influences the development of the environmental domain, including a wide range of geospatial and cartographic information systems, such as Geographic Information Systems (GIS), Multimedia Atlas Information Systems (MAIS) and more recently web-based GIS (Web-GIS). In this context, we introduce web-based environmental geospatial information systems (Web-EGIS) as a special case of Web-GIS, aiming to integrate the functionalities of geospatial information systems with the enormous quantity of specialized, distributed and highly heterogeneous environmental geo-referenced data and services. We define three main characteristics of the Web-EGIS. The first is a generic hypercube-based data organization and visualization. The next characteristic is a standard-based, three-tier service-oriented architecture. The third and last characteristic is the traceability of the architectural and design decisions, for which we introduce the new concept of an ‘Environmental Application Context’, arguing that not only the functional but also the non-functional requirements (NFRs) have an important role in defining the architecture, software components and data services of such systems. In a nutshell, a Web-EGIS is characterized by a coherent user experience through the hypercube-based visualization concept, technically supported by a service-oriented architecture that is structured according to an extensive analysis of NFRs. On this basis, we introduce the Geodata visualization and interactive training environment (GeoVITe) Platform for Interdisciplinary Environmental Research as a reference implementation of a Web-EGIS with its basic design requirements, integrative hypercube-based visualization for heterogeneous data sources, extended web cartography functionalities, and its de facto system architecture. The concept of the hypercube-based visualization is better transferred to the system architecture by understanding the ‘Environmental Application Context’ of this particular Web-EGIS, which also makes it easier to maintain and enhance. The resulting system is a support platform for research activities in the environmental domain.     

An Evidential Reasoning Approach to Land Degradation Evaluation: Dempster-Shafer Theory of Evidence

This study explores the combination of expert and local knowledge for an integrated evaluation of land degradation in southern Mauritania. The expert knowledge uses two imprecise information and uncertainty management tools, Fuzzy measure theory and Dempster‐Shafer theory, mediated by expert knowledge, to integrate data collected using local knowledge. Fuzzy measures were found to be an efficient way of handling uncertainty of data compiled from local environmental knowledge and uniformly scaling all land degradation indicator variables to the same numerical range of values. The two techniques allowed scaling and integration of 13 evidential themes characterizing southern Mauritania. The cartographic outputs of this study show the potential of Fuzzy measure theory and Demspter‐Shafer theory as powerful complementary environmental resource management tools. On a scale of 0.0 to 1.0, the maps indicate the degree of degradation. The seriousness of land degradation decreases from settlements, roads, and watering points outward. As such, they constitute an excellent guide for resource allocation and rehablitation plans.     

Flex框架下网络视频GIS设计与实现

视频GIS支持地理视频数据的管理、发布和交互操作,应用于线形设施管理、地理教育等领域。本文尝试在Flex框架下开发网络视频GIS。基本思路是:使用Adobe FMS发布FLV格式的视频数据,使用ArcGIS Server9.3发布地理空间数据和视频轨迹,通过HTTP协议来获取XML格式的地理视频语义描述,运用网络多媒体开发工具Adobe Flex整合视频、地图和语义描述数据,进而实现地理视频数据的分发、管理、查询检索、跟踪播放和交互索引等功能,并以具有良好用户体验的Flash发布给用户。软件开发实验表明本技术方案是可行的。     

基于GIS的广州市自然灾害信息管理与应急指挥平台的构建

基于GIS平台建立高效的自然灾害管理及应急指挥系统,不仅可以有效管理自然灾害的基本信息、灾害预警的分析信息,并且实现了源信息和结果信息在各相关部门之间的传递。该系统是基于MapGIS平台,充分利用MapGIS平台提供的组件式开发方法、动态扩展地图文档管理等技术进行二次开发搭建而成。该系统的建立为城市自然灾害信息的管理和应急指挥工作提供了新的借鉴。