Needs for real-time interactive visualization of 3D Tiles for massive 3D content on the web-based virtual globe is rapidly increasing, and to achieve this goal, 3D Tiles needs to be correctly geo-referenced to other g...Needs for real-time interactive visualization of 3D Tiles for massive 3D content on the web-based virtual globe is rapidly increasing, and to achieve this goal, 3D Tiles needs to be correctly geo-referenced to other geospatial data on a web-based virtual globe. It is possible to generate 3D Tiles from different kinds of spatial data through various software tools. However, due to various factors the 3D Tile datasets are often poorly or not at all geo-referenced. To tackle this issue, we propose a new 3D WebGIS framework that facilitates dynamic geo-referencing 3D Tiles on the CesiumJS virtual globe.展开更多
Virtual Globes such as Google Earth TM, revolutionize the way scientists conduct their research and the way the general public use geospatial – related data and information. Improvement in the processing power and st...Virtual Globes such as Google Earth TM, revolutionize the way scientists conduct their research and the way the general public use geospatial – related data and information. Improvement in the processing power and storage capacities of computers, along with the increased Internet accessibility and connectivity, has supported the usage of Virtual Globes technologies. Even more, software releases of freely downloadable Virtual Globes, such as Google Earth and NASA World Wind, has sparked an enormous public interest and increased people’s awareness of spatial sciences.In this study, the Virtual Globes (VG) revolution is discussed and a client - server Graphical User Interface (GUI) application is presented. The developed application enables Google Earth TM Application Program Interface and activates spatial analysis, through enhanced JavaScripts and Visual Basic script codes. The main scope was to present the methodology followed during geological modeling along with the application capabilities when handling with data derived from digitized geological maps and field measurements.展开更多
Virtual globes(VGs)allow Internet users to view geographic data of heterogeneous quality created by other users.This article presents a new approach for collecting and visualizing information about the perceived quali...Virtual globes(VGs)allow Internet users to view geographic data of heterogeneous quality created by other users.This article presents a new approach for collecting and visualizing information about the perceived quality of 3D data in VGs.It aims atimproving users’awareness of the qualityof 3D objects.Instead of relying onthe existing metadata or on formal accuracy assessments that are often impossible in practice,we propose a crowd-sourced quality recommender system based on the five-star visualization method successful in other types of Web applications.Four alternative five-star visualizations were implemented in a Google Earth-based prototype and tested through a formal user evaluation.These tests helped identifying the most effective method for a 3D environment.Results indicate that while most websites use a visualization approach that shows a‘number of stars’,this method was the least preferred by participants.Instead,participants ranked the‘number within a star’method highest as it allowed reducing the visual clutter in urban settings,suggesting that 3D environments such as VGs require different designapproachesthan2Dornon-geographicapplications.Resultsalsoconfirmed that expert and non-expert users in geographic data share similar preferences for the most and least preferred visualization methods.展开更多
One of the problems in virtual globes technologies is the real-time representation of vegetal species.In forest or garden representations,the low detailed plants produce a lack of realism.Efficient techniques are requ...One of the problems in virtual globes technologies is the real-time representation of vegetal species.In forest or garden representations,the low detailed plants produce a lack of realism.Efficient techniques are required to achieve accurate interactive visualisation due to the great number of polygons the vegetal species have.This article presents a multi-resolution model based on a geometric representation of vegetal species that allows the application to perform the progressive transmission of the model,that is,the transmission of a simple representation followed by successive refinements of it.It has a hardware-oriented design in order to obtain interactive frame rates.The geometric data of the objects are stored in the graphics processing unit and,moreover,the change from one approximation to another is obtained by performing mathematical calcula-tions in this graphics hardware.The multi-resolution model presented here enables instancing:as many vegetal species as desired can be rendered with different levels of detail,while all of them are accessing the same geometric data.This model has been used to build a real-time representation of a not imaginary scenario.展开更多
Typhoons are usually accompanied by strong winds,heavy rain,storm surges and other disastrous events,and they are the most severe weather phenomena in the western part of the North Pacific Ocean.Visualisation is a key...Typhoons are usually accompanied by strong winds,heavy rain,storm surges and other disastrous events,and they are the most severe weather phenomena in the western part of the North Pacific Ocean.Visualisation is a key technology for analysing and presenting climate simulations and observations together with related social and ecological data.Virtual globes are a logical platform for visualising such geospatial data via the Internet.To implement interactive visualisation of typhoon data within virtual globes,this study provides a 3D texture-mapping algorithm to render volume textures on a globe.In addition,a systematic framework is proposed in which a hierarchical octree-based multiresolution data structure is implemented to organise the large volume dataset,and a graphics processing unit-based dynamic interpolation approach is proposed to obtain a smooth effect.Finally,the structure is combined with a level of detail strategy to enable the rendering of dynamic volumetric data at an acceptable interactive frame rate.To demonstrate the capabilities of this framework,data for a simulated typhoon event were rendered in World Wind,an open-source virtual globe.The experimental results demonstrate that the application of the proposed strategies can result in an interactive visualisation performance that renders typhoon data on virtual globes.展开更多
Pipelines are an important part of urban infrastructure development.As part of a virtual globe(VG),the high-efficiency and high-quality visualization of 3D large-scale and high-density urban pipelines is of great impo...Pipelines are an important part of urban infrastructure development.As part of a virtual globe(VG),the high-efficiency and high-quality visualization of 3D large-scale and high-density urban pipelines is of great importance.This paper proposes a GPU-based pipeline ray casting method for the visualization of urban-scale pipelines in the framework of a VG.The method involves the initial partitioning of the pipeline data into tiles,based on the relationship between the pipeline layer scale and the discrete global grid system(DGGSs).The pipeline centerline in each tile is then segmented and encoded,and a coarser pipeline bounding volume is subsequently constructed using a geometry shader.Finally,the fine 3D pipeline is rendered using a pixel shader.The results of the experimental implementation of the proposed method show that it satisfies the requirements for the multiscale visualization of pipelines in a VG.Moreover,compared with the traditional polygon-based method,the method facilitates a 20%increase in rendering frame rate for the same pixel level accuracy display effect.It also enables the visualization of the thickness of the 3D pipeline without any obvious effect on the rendering efficiency。展开更多
3D city models,which are important items of content on the virtual globe,are characterized by complicated structures and large amounts of data.These factors make the visualization of 3D city models highly dependent up...3D city models,which are important items of content on the virtual globe,are characterized by complicated structures and large amounts of data.These factors make the visualization of 3D city models highly dependent upon the performance of computer hardware.Thus,achieving the efficient rendering of 3D city models using different hardware performance levels represents one of the key problems currently facing researchers.This paper proposes a time-critical adaptive visualization method that first estimates the possible rendering time for each model according to the data structure of the model in addition to the CPU/GPU performance of the computer.It then dynamically adjusts the rendering level for each model based on the results of an estimation of the rendering time to ensure that the final scene can be completed within a given time.To verify the effectiveness and flexibility of this method,it is applied using different computers.The results show that the adaptive visualization method presented in this paper not only can adapt to computers with different levels of performances but also demonstrates an obvious improvement in the time estimation precision,visual effects,and optimization speed relative to existing adaptive visualization methods.展开更多
Massive volumes of global geospatial information are being collected by newly designed acquisition devices and generated by various geospatial applications.This poses a critical challenge to efficiently organize and e...Massive volumes of global geospatial information are being collected by newly designed acquisition devices and generated by various geospatial applications.This poses a critical challenge to efficiently organize and effectively integrate global multi-source geospatial information.This paper introduces a global seamless data model for the organization of huge multi-source,multi-resolution and multi-temporal geospatial data.Based on this data model,the management of the global multi-resolution pyramid is discussed in detail.To integrate geospatial data and processing functions from various GIS systems,a service-oriented framework is presented through the technology of Virtual Globe.Finally,a Virtual Globe system,GeoGlobe,is developed and illustrated.展开更多
Virtual globe has been recognized as an appealing technology to support the digital earth.It provides an intuitive and appealing way to visualize geospatial information,and is being used frequently to bring the globe-...Virtual globe has been recognized as an appealing technology to support the digital earth.It provides an intuitive and appealing way to visualize geospatial information,and is being used frequently to bring the globe-scale geospatial information to our fingertips.The easy access to virtual globes such as Google Earth,Microsoft Virtual Earth,and NASA World Wind allows both the general public users and professionals to use them for educational and research purposes.While virtual globes provide a number of functions for geospatial data visualization and annotation,the geospatial analysis functions available in the current virtual globes are limited.This paper addresses an approach to the establishment of an analysis-enhanced virtual globe.The approach is based on the integration of virtual globe and interoperable geoprocessing services.Such an analysis-enhanced virtual globe combines the visualization and communication power of virtual globes with the conventional powerful analysis functions of GIS,thus meeting the analysis demands in digital earth.展开更多
How to integrate and disseminate globally distributed multi-source and heterogeneous spatial information is an open problem in integration and sharing service of geographic information.Here we propose a new service ar...How to integrate and disseminate globally distributed multi-source and heterogeneous spatial information is an open problem in integration and sharing service of geographic information.Here we propose a new service architecture suitable for integration and sharing of distributed multi-source geographic information.We also propose a global virtual pyramid model,which can be applied in 3D virtual globes.In view of the difficulty of web multi-node geographic information sharing service,we propose a web multi-node service aggregation method,integrated in our autonomously developed virtual globe platform GeoGlobe and introduced in the National Platform for Common GeoSpatial Information Services named"TIANDITU".It achieves2D and 3D integration for geographic information service.展开更多
We present a method to represent multi-resolution vector graphics such as road networks or railway networks in virtual environment. These vector data can be interactively edited and the landscape and be explored in re...We present a method to represent multi-resolution vector graphics such as road networks or railway networks in virtual environment. These vector data can be interactively edited and the landscape and be explored in real time at any altitude from flight view to car view. We design a context-focused vector description of linear can areal features, with associated customized definition painter to specify their appearance （color and material） and their display mode （detailed mode or simplified mode）. There are some special problems in drawing vector graphics in virtual environment. Floating-point round-off error appear when we use a low view point to observe the scene, and it leads to scene jittering. Drawing 3D wide lines turns into a problem on 3D terrain. We design a view-based self-adaptive interpolation algorithm and an offset line generating algorithm to solve it. Our results show high performance with good visual quality.展开更多
文摘Needs for real-time interactive visualization of 3D Tiles for massive 3D content on the web-based virtual globe is rapidly increasing, and to achieve this goal, 3D Tiles needs to be correctly geo-referenced to other geospatial data on a web-based virtual globe. It is possible to generate 3D Tiles from different kinds of spatial data through various software tools. However, due to various factors the 3D Tile datasets are often poorly or not at all geo-referenced. To tackle this issue, we propose a new 3D WebGIS framework that facilitates dynamic geo-referencing 3D Tiles on the CesiumJS virtual globe.
文摘Virtual Globes such as Google Earth TM, revolutionize the way scientists conduct their research and the way the general public use geospatial – related data and information. Improvement in the processing power and storage capacities of computers, along with the increased Internet accessibility and connectivity, has supported the usage of Virtual Globes technologies. Even more, software releases of freely downloadable Virtual Globes, such as Google Earth and NASA World Wind, has sparked an enormous public interest and increased people’s awareness of spatial sciences.In this study, the Virtual Globes (VG) revolution is discussed and a client - server Graphical User Interface (GUI) application is presented. The developed application enables Google Earth TM Application Program Interface and activates spatial analysis, through enhanced JavaScripts and Visual Basic script codes. The main scope was to present the methodology followed during geological modeling along with the application capabilities when handling with data derived from digitized geological maps and field measurements.
文摘Virtual globes(VGs)allow Internet users to view geographic data of heterogeneous quality created by other users.This article presents a new approach for collecting and visualizing information about the perceived quality of 3D data in VGs.It aims atimproving users’awareness of the qualityof 3D objects.Instead of relying onthe existing metadata or on formal accuracy assessments that are often impossible in practice,we propose a crowd-sourced quality recommender system based on the five-star visualization method successful in other types of Web applications.Four alternative five-star visualizations were implemented in a Google Earth-based prototype and tested through a formal user evaluation.These tests helped identifying the most effective method for a 3D environment.Results indicate that while most websites use a visualization approach that shows a‘number of stars’,this method was the least preferred by participants.Instead,participants ranked the‘number within a star’method highest as it allowed reducing the visual clutter in urban settings,suggesting that 3D environments such as VGs require different designapproachesthan2Dornon-geographicapplications.Resultsalsoconfirmed that expert and non-expert users in geographic data share similar preferences for the most and least preferred visualization methods.
基金This work was supported by the Spanish Ministry of Science and Technology(Project TIN2010-21089-C03-03)Feder Funds and Generalitat Valenciana(Project PROMETEO/2010/028).
文摘One of the problems in virtual globes technologies is the real-time representation of vegetal species.In forest or garden representations,the low detailed plants produce a lack of realism.Efficient techniques are required to achieve accurate interactive visualisation due to the great number of polygons the vegetal species have.This article presents a multi-resolution model based on a geometric representation of vegetal species that allows the application to perform the progressive transmission of the model,that is,the transmission of a simple representation followed by successive refinements of it.It has a hardware-oriented design in order to obtain interactive frame rates.The geometric data of the objects are stored in the graphics processing unit and,moreover,the change from one approximation to another is obtained by performing mathematical calcula-tions in this graphics hardware.The multi-resolution model presented here enables instancing:as many vegetal species as desired can be rendered with different levels of detail,while all of them are accessing the same geometric data.This model has been used to build a real-time representation of a not imaginary scenario.
基金This research was supported by the Key Knowledge Innovative Project of the Chinese Academy of Sciences[KZCX2-EW-318]the Jiashan Science and Technology Projects[2011A44,2011B04]the State Science and Technology Support Plan[2012BAH33B04].
文摘Typhoons are usually accompanied by strong winds,heavy rain,storm surges and other disastrous events,and they are the most severe weather phenomena in the western part of the North Pacific Ocean.Visualisation is a key technology for analysing and presenting climate simulations and observations together with related social and ecological data.Virtual globes are a logical platform for visualising such geospatial data via the Internet.To implement interactive visualisation of typhoon data within virtual globes,this study provides a 3D texture-mapping algorithm to render volume textures on a globe.In addition,a systematic framework is proposed in which a hierarchical octree-based multiresolution data structure is implemented to organise the large volume dataset,and a graphics processing unit-based dynamic interpolation approach is proposed to obtain a smooth effect.Finally,the structure is combined with a level of detail strategy to enable the rendering of dynamic volumetric data at an acceptable interactive frame rate.To demonstrate the capabilities of this framework,data for a simulated typhoon event were rendered in World Wind,an open-source virtual globe.The experimental results demonstrate that the application of the proposed strategies can result in an interactive visualisation performance that renders typhoon data on virtual globes.
文摘Pipelines are an important part of urban infrastructure development.As part of a virtual globe(VG),the high-efficiency and high-quality visualization of 3D large-scale and high-density urban pipelines is of great importance.This paper proposes a GPU-based pipeline ray casting method for the visualization of urban-scale pipelines in the framework of a VG.The method involves the initial partitioning of the pipeline data into tiles,based on the relationship between the pipeline layer scale and the discrete global grid system(DGGSs).The pipeline centerline in each tile is then segmented and encoded,and a coarser pipeline bounding volume is subsequently constructed using a geometry shader.Finally,the fine 3D pipeline is rendered using a pixel shader.The results of the experimental implementation of the proposed method show that it satisfies the requirements for the multiscale visualization of pipelines in a VG.Moreover,compared with the traditional polygon-based method,the method facilitates a 20%increase in rendering frame rate for the same pixel level accuracy display effect.It also enables the visualization of the thickness of the 3D pipeline without any obvious effect on the rendering efficiency。
基金the National Key R&D Program of China[grant number 2017YFB0503703]The Nature Science Foundation Innovation Group Project of Hubei Province,China[grant number 2016CFA003]The LIESMARS Special Research Funding。
文摘3D city models,which are important items of content on the virtual globe,are characterized by complicated structures and large amounts of data.These factors make the visualization of 3D city models highly dependent upon the performance of computer hardware.Thus,achieving the efficient rendering of 3D city models using different hardware performance levels represents one of the key problems currently facing researchers.This paper proposes a time-critical adaptive visualization method that first estimates the possible rendering time for each model according to the data structure of the model in addition to the CPU/GPU performance of the computer.It then dynamically adjusts the rendering level for each model based on the results of an estimation of the rendering time to ensure that the final scene can be completed within a given time.To verify the effectiveness and flexibility of this method,it is applied using different computers.The results show that the adaptive visualization method presented in this paper not only can adapt to computers with different levels of performances but also demonstrates an obvious improvement in the time estimation precision,visual effects,and optimization speed relative to existing adaptive visualization methods.
基金supported by the Natural Science Foundation of China (Grant No.40801163)the Innovation Research Group of NSFC (Grant No.40721001)the National Basic Research Program of China ("973" Program)(Grant No.2006CB701304)
文摘Massive volumes of global geospatial information are being collected by newly designed acquisition devices and generated by various geospatial applications.This poses a critical challenge to efficiently organize and effectively integrate global multi-source geospatial information.This paper introduces a global seamless data model for the organization of huge multi-source,multi-resolution and multi-temporal geospatial data.Based on this data model,the management of the global multi-resolution pyramid is discussed in detail.To integrate geospatial data and processing functions from various GIS systems,a service-oriented framework is presented through the technology of Virtual Globe.Finally,a Virtual Globe system,GeoGlobe,is developed and illustrated.
基金supported by the National Hi-Tech Research and Development Program of China ("863" Project) (Grant Nos.2007AA12Z214,2007AA120501)2009 International Society for Photogrammetry and Remote Sensing Scientific Project,the National Natural Science Foundation of China (Grant Nos.40801153,40721001)+1 种基金the National Basic Re-search Program of China ("973" Project) (Grant No.2006CB701304)LIESMARS and SKLSE (Wuhan University) Special Research Fundings
文摘Virtual globe has been recognized as an appealing technology to support the digital earth.It provides an intuitive and appealing way to visualize geospatial information,and is being used frequently to bring the globe-scale geospatial information to our fingertips.The easy access to virtual globes such as Google Earth,Microsoft Virtual Earth,and NASA World Wind allows both the general public users and professionals to use them for educational and research purposes.While virtual globes provide a number of functions for geospatial data visualization and annotation,the geospatial analysis functions available in the current virtual globes are limited.This paper addresses an approach to the establishment of an analysis-enhanced virtual globe.The approach is based on the integration of virtual globe and interoperable geoprocessing services.Such an analysis-enhanced virtual globe combines the visualization and communication power of virtual globes with the conventional powerful analysis functions of GIS,thus meeting the analysis demands in digital earth.
基金supported by the National Natural Science Foundation of China(Grant No.41023001)National Basic Research Program of China(Grant No.2012CB719906)Innovative Research Groups Supported Project of the National Natural Science Foundation of China(Grant No.41021061)
文摘How to integrate and disseminate globally distributed multi-source and heterogeneous spatial information is an open problem in integration and sharing service of geographic information.Here we propose a new service architecture suitable for integration and sharing of distributed multi-source geographic information.We also propose a global virtual pyramid model,which can be applied in 3D virtual globes.In view of the difficulty of web multi-node geographic information sharing service,we propose a web multi-node service aggregation method,integrated in our autonomously developed virtual globe platform GeoGlobe and introduced in the National Platform for Common GeoSpatial Information Services named"TIANDITU".It achieves2D and 3D integration for geographic information service.
基金Supported by National Basic Research Program of China (973 Program,No.2010CB328002)National Natural Science Foundation of China (Nos.61232014,61121002,61173080)National Key Technology Research and Development Program of China (No.2013BAK03B07)
文摘We present a method to represent multi-resolution vector graphics such as road networks or railway networks in virtual environment. These vector data can be interactively edited and the landscape and be explored in real time at any altitude from flight view to car view. We design a context-focused vector description of linear can areal features, with associated customized definition painter to specify their appearance （color and material） and their display mode （detailed mode or simplified mode）. There are some special problems in drawing vector graphics in virtual environment. Floating-point round-off error appear when we use a low view point to observe the scene, and it leads to scene jittering. Drawing 3D wide lines turns into a problem on 3D terrain. We design a view-based self-adaptive interpolation algorithm and an offset line generating algorithm to solve it. Our results show high performance with good visual quality.
