Geospatial Data Visualization Research Articles

Geospatial and Simulation a Point of Convergence

Abstract. As 3D visualisation of geospatial data has become more prominent over the last decade within the Mapping and Geospatial communities, they have begun to use various techniques and processes that have previously been used by the Simulation community. In the reverse the Simulation community has progressively been making wider use of rich sources of geospatial data as the basis of terrain models. This has partly been facilitated by a continued development of processing ability of computers enabling the 3D display of geospatial data on a broader range of devices including mobile platforms.In the past the Geospatial and Simulation communities have worked relatively independent from each other. This has subsequently led the Simulation community to manage geospatial data so that it would support their applications in the generation of terrains in both 2D and 3D.The study will look at the two fields and how they have come together over the years. It will also consider how the evolution of standards are having an impact on the two communities and the trends that are happening within 3D mapping and simulation that are influencing and driving these changes.Lessons learned from the Simulation community and how its work can help in a range of topics including generalisation in visualisation of data, will be given. The study will be able to offer views and perspectives of 3D visualisation in mapping presented by someone who has a Geospatial background and spent a decade using geospatial knowledge to support simulation research and has worked on generating 3D virtual representations and exploited the output for a range of purposes. Details of how the two communities can work together in the future to benefit from a mutual understanding of each other’s needs and requirements will also be given.

EXTRACTION AND VISUALIZATION OF 3D BUILDING MODELS IN URBAN AREAS FOR FLOOD SIMULATION

Abstract. Floods pose a risk that is likely to worsen in the future due to climate change. Therefore, it is essential that decision makers and domain experts have the tools to evaluate the effects of floods. We developed a tool that visualizes the earth and buildings in three dimensions to simulate floods so that effective strategies can be developed to enhance resilience and mitigate the effects of floods. We opted to use open standards and free and open source software (FOSS) for Web to maximize interoperability, replicability, reusability, and accessibility. As a result of the literature review, we decided to use CityGML and CesiumJS for three-dimensional geospatial data visualization. However, as CityGML data is not available for the cities that our project focuses on, we developed software called shp2city that converts Esri shapefile to CityGML data in LOD1 or LOD2. Moreover, as CityGML data cannot be immediately used with CesiumJS, we used 3DCityDB to store, represent, and manage the CityGML data; 3DCityDB Importer/Exporter to export the CityGML data in KML/COLLADA/glTF format to be used within the 3DCityDB Web-Map-Client that is based on CesiumJS for visualization. Finally, we simulated floods to aid in the informed decision-making process regarding adaptation measures and mitigation of flooding effects.

Visualising Combined Time Use Patterns of Children's Activities and Their Association with Weight Status and Neighbourhood Context.

Compositional data techniques are an emerging method in physical activity research. These techniques account for the complexities of, and interrelationships between, behaviours that occur throughout a day (e.g., physical activity, sitting, and sleep). The field of health geography research is also developing rapidly. Novel spatial techniques and data visualisation approaches are increasingly being recognised for their utility in understanding health from a socio-ecological perspective. Linking compositional data approaches with geospatial datasets can yield insights into the role of environments in promoting or hindering the health implications of the daily time-use composition of behaviours. The 7-day behaviour data used in this study were derived from accelerometer data for 882 Auckland school children and linked to weight status and neighbourhood deprivation. We developed novel geospatial visualisation techniques to explore activity composition over a day and generated new insights into links between environments and child health behaviours and outcomes. Visualisation strategies that integrate compositional activities, time of day, weight status, and neighbourhood deprivation information were devised. They include a ringmap overview, small-multiple ringmaps, and individual and aggregated time–activity diagrams. Simultaneous visualisation of geospatial and compositional behaviour data can be useful for triangulating data from diverse disciplines, making sense of complex issues, and for effective knowledge translation.

Geo-Gap Tree: A Progressive Query and Visualization Method for Massive Spatial Data

Online visualization and query of massive geo-spatial data are facing increasing challenges with the explosive growth of location-based spatial datasets. In the practical scenario, online visualization is carried out in a progressive way, namely, a sketchy view map is first presented, and more detailed view maps are produced gradually as the viewport scale goes deeper. One approach is to use the multi-scale spatial index technique. However, it loses the original data attribute and cannot provide spatial statistics information. The paper is to provide an improved index structure, the Geo-Gap tree, which aims to enhance online interactive access to large spatial datasets, as well as enable one to compute statistical attributes like aggregation at the coarse level. Therefore, the first focus of Geo-Gap tree is improving the efficiency of tree building. For this purpose, an adaptive geohash coding is introduced to reduce the computing of neighboring objects. And, this phase can be improved in parallel once objects are partitioned. Compare to Gap tree, the cost of building the Geo-Gap tree can be greatly reduced. The second contribution is to choose data at different level based on sampling so that a sample for each level can be served as a progressive query result. The third contribution is an estimation of progressive query results, which ensure that progressive query accuracy can be controlled within the range of theoretical analysis. With the query continuing to execute, the query results become more and more accurate. The method is now integrated successfully into a high-performance geographic information system called HiGIS.

Three-Dimensional Rule-Based City Modelling to Support Urban Redevelopment Process

Multi-dimensional representation of urban settings has received a great deal of attention among urban planners, policy makers, and urban scholars. This is due to the fact that cities grow vertically and new urbanism strategies encourage higher density and compact city development. Advancements in computer technology and multi-dimensional geospatial data integration, analysis and visualisation play a pivotal role in supporting urban planning and design. However, due to the complexity of the models and technical requirements of the multi-dimensional city models, planners are yet to fully exploit such technologies in their activities. This paper proposes a workflow to support non-experts in using three-dimensional city modelling tools to carry out planning control amendments and assess their implications. The paper focuses on using a parametric three-dimensional (3D) city model to enable planners to measure the physical (e.g., building height, shadow, setback) and functional (e.g., mix of land uses) impacts of new planning controls. The workflow is then implemented in an inner suburb of Metropolitan Melbourne, where urban intensification strategies require the planners to carry out radical changes in regulations. This study demonstrates the power of the proposed 3D visualisation tool for urban planners at taking two-dimensional (2D) Geographic Information System (GIS) procedural modelling to construct a 3D model.

WEB BASED 3D VISUALISATION OF TIME-VARYING AIR QUALITY INFORMATION

Abstract. Many countries where the industrial development and production rates are high face many side effects of low air quality and air pollution. There is an evident correlation between the topographic and climatic properties of a location and the air pollution and air quality on that location. As the variation of air quality is dependent on location, air quality information should be acquired, utilised, stored and presented in form of Geo-Information. On the other hand, as this information is related with the health concerns of public, the information should be available publicly, and needs to be presented through an easily accessible medium and through a commonly used interface. Efficient storage of time-varying air quality information when combined with an efficient mechanism of 3D web-based visualisation would help very much in dissemination of air quality information to public. This research is focused on web-based 3D visualisation of time-varying air quality data. A web based interactive system is developed to visualise pollutant levels that were acquired as hourly intervals from more than 100 stations in Turkey between years 2008 and 2017. The research also concentrated on visualisation of geospatial high volume data. In the system, visualisation can be achieved on-demand by querying an air pollutant information database of 10.330.629 records and a city object database with more than 700.000 records. The paper elaborates on the details of this research. Following a background on air quality, air quality models, and Geo-Information visualisation, the system architecture and functionality is presented. The paper concludes with results of usability tests of the system.

Design and Implementation of a 4D Web Application for Analytical Visualization of Smart City Applications

Contemporary development of computer hardware and software, WebGIS and geo-web services as well as the availability of semantic 3D city models, facilitate flexible and dynamic implementation of web applications. The aim of this paper is to introduce 4D CANVAS, a web-based application for dynamic visualization of 3D geospatial data for improved decision making in smart city applications. It is based on the Cesium Virtual Globe, an open-source JavaScript library developed with HTML5 and WebGL. At first, different data formats such as JSON, GeoJSON, Cesium Markup Language (CZML) and 3D Tiles are evaluated for their suitability in 4D visualization applications. Then, an interactive Graphical User Interface (GUI) is built observing the principle of cartographic standards to view, manage, understand and explore different simulation outputs at multiple spatial (3D surface of buildings) and temporal (hourly, daily, monthly) resolutions. In this regard, multiple tools such as aggregation, data classification, etc. are developed utilizing JavaScript libraries. As a proof of concept, two energy simulations and their outputs of different spatial and temporal resolutions are demonstrated in five Asian and European cities. Finally, the 4D CANVAS is deployed both in desktop and multi-touch screens. The proposed application allows easy integration of any other geospatial simulation results, thereby helps the users from different sectors to explore them interactively in 4D.

A Formalized 3D Geovisualization Illustrated to Selectivity Purpose of Virtual 3D City Model

Virtual 3D city models act as valuable central information hubs supporting many aspects of cities, from management to planning and simulation. However, we noted that 3D city models are still underexploited and believe that this is partly due to inefficient visual communication channels across 3D model producers and the end-user. With the development of a formalized 3D geovisualization approach, this paper aims to support and make the visual identification and recognition of specific objects in the 3D models more efficient and useful. The foundation of the proposed solution is a knowledge network of the visualization of 3D geospatial data that gathers and links mapping and rendering techniques. To formalize this knowledge base and make it usable as a decision-making system for the selection of styles, second-order logic is used. It provides a first set of efficient graphic design guidelines, avoiding the creation of graphical conflicts and thus improving visual communication. An interactive tool is implemented and lays the foundation for a suitable solution for assisting the visualization process of 3D geospatial models within CAD and GIS-oriented software. Ultimately, we propose an extension to OGC Symbology Encoding in order to provide suitable graphic design guidelines to web mapping services.

A redesign of OGC Symbology Encoding standard for sharing cartography.

Despite most Spatial Data Infrastructures offering service-based visualization of geospatial data, requirements are often at a very basic level leading to poor quality of maps. This is a general observation for any geospatial architecture as soon as open standards as those of the Open Geospatial Consortium (OGC) are applied. To improve the situation, this paper does focus on improvements at the portrayal interoperability side by considering standardization aspects. We propose two major redesign recommendations. First to consolidate the cartographic theory at the core of the OGC Symbology Encoding standard. Secondly to build the standard in a modular way so as to be ready to be extended with upcoming future cartographic requirements. Thus, we start by defining portrayal interoperability by means of typical-use cases that frame the concept of sharing cartography. Then we bring to light the strengths and limits of the relevant open standards to consider in this context. Finally we propose a set of recommendations to overcome the limits so as to make these use cases a true reality. Even if the definition of a cartographic-oriented standard is not able to act as a complete cartographic design framework by itself, we argue that pushing forward the standardization work dedicated to cartography is a way to share and disseminate good practices and finally to improve the quality of the visualizations.

LSIVIEWER 2.0 – A CLIENT-ORIENTED ONLINE VISUALIZATION TOOL FOR GEOSPATIAL VECTOR DATA

Abstract. Geospatial data visualization systems have been predominantly through applications that are installed and run in a desktop environment. Over the last decade, with the advent of web technologies and its adoption by Geospatial community, the server-client model for data handling, data rendering and visualization respectively has been the most prevalent approach in Web-GIS. While the client devices have become functionally more powerful over the recent years, the above model has largely ignored it and is still in a mode of serverdominant computing paradigm. In this paper, an attempt has been made to develop and demonstrate LSIViewer – a simple, easy-to-use and robust online geospatial data visualisation system for the user’s own data that harness the client’s capabilities for data rendering and user-interactive styling, with a reduced load on the server. The developed system can support multiple geospatial vector formats and can be integrated with other web-based systems like WMS, WFS, etc. The technology stack used to build this system is Node.js on the server side and HTML5 Canvas and JavaScript on the client side. Various tests run on a range of vector datasets, upto 35 MB, showed that the time taken to render the vector data using LSIViewer is comparable to a desktop GIS application, QGIS, over an identical system.

Visual subsetting, conversion and complex query exploitation in large spatio-temporal databases

In recent years, large amounts of multidimensional data are being generated at a rapid pace, creating the need to: develop appropriate tools for visual data analytics and for enhancing accessibility and discoverability of the data; and new algorithms and methods for seamless integration, manipulation and interactive visualization of data. We describe an interactive tool and technique for data mining and visualization, called SubVizCon that integrates advanced concepts for spatio-temporal databases with interactive visualization capabilities of the geographic information system software. More specifically, we illustrate the development and implementation of the SubVizCon framework, which integrates geospatial data analysis, feature extraction, and visualization functions in ArcGIS with the advanced subsetting and querying functions of the Parametric Database Model. The seamless integration and interoperability of these software tools within SubVizCon framework enables users to not only visualize large amounts of data but also discover spatio-temporal patterns that might otherwise remain hidden.

GIS-based visualization of integrated highway maintenance and construction planning: a case study of Fort Worth, Texas

BackgroundThis paper reports on a case study of the use of visualization of geospatial data that is distributed across data sets and requires integration over time and space to aid decision makers. Like many State Highway Agencies (SHAs) in the United States, the Texas Department of Transportation (TxDOT) is organized along the traditional functional lines of planning, design, construction, maintenance, and operations. It has historically relied on experience and longevity of its staff to efficiently and effectively plan its construction and maintenance projects. Although functional boundaries of maintenance and construction are fairly clearly defined, there tends to be some overlap in projects that can be executed by either of the functional groups. The department currently does not have a robust integrated information system for identifying potential planning conflicts between its construction and maintenance projects. This has led to suboptimal use of resources, including overlapping plans for maintenance and mobility enhancement projects.Case descriptionWith over 650 highway projects assigned across two functional groups within the district’s (TxDOT Fort Worth district) boundary, it is a challenging task to assemble a coherent plan for managing these projects over a multi-year planning period that is subject to external stakeholder input as well as shifting funding constraints. Temporal and spatial data needed for integrated planning resides in specialized information systems developed for the needs of individual functional groups. To address this challenge, this district decided to integrate and visualize data from individual information systems in a Geographic Information System (GIS). A GIS-based tool was developed to integrate, visualize, and analyze projects data from multiple information systems.Discussion and evaluationThis paper documents the benefits associated with visualization and integration of projects data in a GIS to address planning challenges facing a typical highway agency. Among the lessons learned are the potential uses of GIS, which include detecting spatially and temporally overlapping projects, supporting integrated planning, and improving communication among functional groups within a state highway agency.ConclusionThe study demonstrates that such spatial-temporal representations of project data can lead to early identification of potential overlaps during the planning phase. In a broader context, such geospatial visualization efforts can also form the basis for eliciting practitioners’ perspectives and knowledge input in the development of spatial decision support systems.

The architecture for data, security and application in Digital Earth platform

Digital Earth platform is an application, service and decision support system, which integrates geo-spatial data acquisition, transmission, storage, processing, analysis, statistics and visualization. It realizes comprehensive management and widely application of different kinds of huge earth data under the geo-spatial framework and in a open environment. It should consider the continues growing of data and applications, as well as data security. According to the issues of how to safely use spatial data in Digital Earth platform, an architecture for data,security and application in Digital Earth platform was proposed in this paper. We call this architecture DOA(DOSA). In the digital earth platform on its goal is the Trusted Data. DOA(DOSA) and Trusted Data can provide data management, security grantee, application supporting for Digital Earth platform.

Development of climate data storage and processing model

We present a storage and processing model for climate datasets elaborated in the framework of a virtual research environment (VRE) for climate and environmental monitoring and analysis of the impact of climate change on the socio-economic processes on local and regional scales. The model is based on a «shared nothings» distributed computing architecture and assumes using a computing network where each computing node is independent and selfsufficient. Each node holds a dedicated software for the processing and visualization of geospatial data providing programming interfaces to communicate with the other nodes. The nodes are interconnected by a local network or the Internet and exchange data and control instructions via SSH connections and web services. Geospatial data is represented by collections of netCDF files stored in a hierarchy of directories in the framework of a file system. To speed up data reading and processing, three approaches are proposed: a precalculation of intermediate products, a distribution of data across multiple storage systems (with or without redundancy), and caching and reuse of the previously obtained products. For a fast search and retrieval of the required data, according to the data storage and processing model, a metadata database is developed. It contains descriptions of the space-time features of the datasets available for processing, their locations, as well as descriptions and run options of the software components for data analysis and visualization. The model and the metadata database together will provide a reliable technological basis for development of a high- performance virtual research environment for climatic and environmental monitoring.

Web-GIS based Framework for Solid Waste Complaint Management for Sustainable and Smart City

Geographical information system (GIS), data management and digital technology play a key role in the development of sustainable city. These technologies help administrator and planner to increase performance, utilize resources efficiently, reduce cost and engage the citizen in the system, which makes the city smarter. Basic infrastructure component that makes the city smarter include transport, energy, healthcare, water and waste management. The present study is aimed to develop Web-GIS based framework for the lodging complaint, visualization and monitoring for solid waste in an urban area. A Web-GIS based framework is presented that uses free open-source software (FOSS) such as open layer, Javascript, Apache tomcat, Geoserver and PostgreSQL/PostGIS for visualization and monitoring of geospatial data. Using this framework a Geo-locator tool is developed to find the locations of facility (bins) to end user for reporting and lodging complain etc. It also develops automatic report for municipal officers to quickly respond to the complaints.

Web GIS based Framework for Citizen Reporting on Collection of Solid Waste and Mapping in GIS for Allahabad City

GIS, remote sensing, digital technology and data management play a key role in the development of sustainable city. With the help of technology, it is possible to increase performance, reduce cost, utilize resources efficiently and engage the citizen in the system that makes the city smarter. Basic infrastructure component that makes the city smarter include transport, energy, healthcare, water and waste. The present study is aimed to develop WebGIS based framewrk for the visualization, monitoring and citizen reporting system for solid waste in an urban area. A WebGIS based framework is presented that uses open source software such as open layer, Javascript, Apache tomcat, Geoserver, PostgreSQL/PostGIS and MySQL for visualization and monitoring of geospatial data. Using this framework a Geo-locator tool is developed to find the locations of facility to end user for reporting and lodging complain etc. It also develops automatic report for municipal officers to quickly respond to the complaints.

3D GIS FOR FLOOD MODELLING IN RIVER VALLEYS

Abstract. The objective of this study is implementation of system architecture for collecting and analysing data as well as visualizing results for hydrodynamic modelling of flood flows in river valleys using remote sensing methods, tree-dimensional geometry of spatial objects and GPU multithread processing. The proposed solution includes: spatial data acquisition segment, data processing and transformation, mathematical modelling of flow phenomena and results visualization. Data acquisition segment was based on aerial laser scanning supplemented by images in visible range. Vector data creation was based on automatic and semiautomatic algorithms of DTM and 3D spatial features modelling. Algorithms for buildings and vegetation geometry modelling were proposed or adopted from literature. The implementation of the framework was designed as modular software using open specifications and partially reusing open source projects. The database structure for gathering and sharing vector data, including flood modelling results, was created using PostgreSQL. For the internal structure of feature classes of spatial objects in a database, the CityGML standard was used. For the hydrodynamic modelling the solutions of Navier-Stokes equations in two-dimensional version was implemented. Visualization of geospatial data and flow model results was transferred to the client side application. This gave the independence from server hardware platform. A real-world case in Poland, which is a part of Widawa River valley near Wroclaw city, was selected to demonstrate the applicability of proposed system.

3D GIS FOR FLOOD MODELLING IN RIVER VALLEYS

The objective of this study is implementation of system architecture for collecting and analysing data as well as visualizing results for hydrodynamic modelling of flood flows in river valleys using remote sensing methods, tree-dimensional geometry of spatial objects and GPU multithread processing. The proposed solution includes: spatial data acquisition segment, data processing and transformation, mathematical modelling of flow phenomena and results visualization. Data acquisition segment was based on aerial laser scanning supplemented by images in visible range. Vector data creation was based on automatic and semiautomatic algorithms of DTM and 3D spatial features modelling. Algorithms for buildings and vegetation geometry modelling were proposed or adopted from literature. The implementation of the framework was designed as modular software using open specifications and partially reusing open source projects. The database structure for gathering and sharing vector data, including flood modelling results, was created using PostgreSQL. For the internal structure of feature classes of spatial objects in a database, the CityGML standard was used. For the hydrodynamic modelling the solutions of Navier-Stokes equations in two-dimensional version was implemented. Visualization of geospatial data and flow model results was transferred to the client side application. This gave the independence from server hardware platform. A real-world case in Poland, which is a part of Widawa River valley near Wroclaw city, was selected to demonstrate the applicability of proposed system.

A VIRTUAL GLOBE-BASED MULTI-RESOLUTION TIN SURFACE MODELING AND VISUALIZETION METHOD

Abstract. The integration and visualization of geospatial data on a virtual globe play an significant role in understanding and analysis of the Earth surface processes. However, the current virtual globes always sacrifice the accuracy to ensure the efficiency for global data processing and visualization, which devalue their functionality for scientific applications. In this article, we propose a high-accuracy multi-resolution TIN pyramid construction and visualization method for virtual globe. Firstly, we introduce the cartographic principles to formulize the level of detail (LOD) generation so that the TIN model in each layer is controlled with a data quality standard. A maximum z-tolerance algorithm is then used to iteratively construct the multi-resolution TIN pyramid. Moreover, the extracted landscape features are incorporated into each-layer TIN, thus preserving the topological structure of terrain surface at different levels. In the proposed framework, a virtual node (VN)-based approach is developed to seamlessly partition and discretize each triangulation layer into tiles, which can be organized and stored with a global quad-tree index. Finally, the real time out-of-core spherical terrain rendering is realized on a virtual globe system VirtualWorld1.0. The experimental results showed that the proposed method can achieve an high-fidelity terrain representation, while produce a high quality underlying data that satisfies the demand for scientific analysis.

A VIRTUAL GLOBE-BASED MULTI-RESOLUTION TIN SURFACE MODELING AND VISUALIZETION METHOD

The integration and visualization of geospatial data on a virtual globe play an significant role in understanding and analysis of the Earth surface processes. However, the current virtual globes always sacrifice the accuracy to ensure the efficiency for global data processing and visualization, which devalue their functionality for scientific applications. In this article, we propose a high-accuracy multi-resolution TIN pyramid construction and visualization method for virtual globe. Firstly, we introduce the cartographic principles to formulize the level of detail (LOD) generation so that the TIN model in each layer is controlled with a data quality standard. A maximum z-tolerance algorithm is then used to iteratively construct the multi-resolution TIN pyramid. Moreover, the extracted landscape features are incorporated into each-layer TIN, thus preserving the topological structure of terrain surface at different levels. In the proposed framework, a virtual node (VN)-based approach is developed to seamlessly partition and discretize each triangulation layer into tiles, which can be organized and stored with a global quad-tree index. Finally, the real time out-of-core spherical terrain rendering is realized on a virtual globe system VirtualWorld1.0. The experimental results showed that the proposed method can achieve an high-fidelity terrain representation, while produce a high quality underlying data that satisfies the demand for scientific analysis.