The scene-rendering mechanism based on binocular vision is one of the key techniques for the VR globe to achieve immersion-type visualization of global 3D scenes.However,this special rendering mechanism also requires ...The scene-rendering mechanism based on binocular vision is one of the key techniques for the VR globe to achieve immersion-type visualization of global 3D scenes.However,this special rendering mechanism also requires that the 3D scene is continuously drawn twice within one frame,which significantly affects the rendering efficiency of VR globes.Therefore,we propose a binocular parallel rendering method.This method first improves the current rendering process of VR globes by assigning the rendering tasks for the left and right camera of VR to be processed on different CPU cores,thereby achieving parallel rendering of binocular scenes.Second,due to the problem of inconsistent resolution of binocular scenes caused by different viewpoints for the left and right cameras,we propose a resolution synchronize algorithm.this algorithm conducts realtime synchronization on the resolution of scene in the rendering process and thus avoids the problem of erroneous binocular stereo matching.Finally,we validate the effectiveness of the method in this paper through experiments.The results of experiments indicate that while the method in this paper can ensure the consistency of binocular scene resolution,it can decrease the frame time of VR globes by approximately 27%on average.展开更多
Science and policy increasingly request for sustainable development and growth.Similarly,Digital Earth undergoes a paradigm shift to an open platform that actively supports user engagement.While the public becomes abl...Science and policy increasingly request for sustainable development and growth.Similarly,Digital Earth undergoes a paradigm shift to an open platform that actively supports user engagement.While the public becomes able to contribute new content,we recognize a gap in user-driven validation,feedback and requirements capture,and innovative application development.Rather than defining Digital Earth applications top down,we see a need for methods and tools that will help building applications bottom up and driven by community needs.These should include a technology toolbox of geospatial and environ-mental enablers,which allow to access functional building blocks and content in multiple ways,but-equally important-enable the collaboration within partially unknown stakeholder networks.The validation and testing in real-life scenarios will be a central requirement when approaching the Digital Earth 2020 goals,which were articulated recently.We particularly argue to follow a Living Lab approach for co-creation and awareness rising in relation to environmental and geospatial matters.We explain why and how such a Digital Earth Living Lab could lead to a sustainable approach for developing,deploying,and using Digital Earth applications and suggest a paradigm shift for Virtual Globes becoming forums for research and innovation.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
The combination of virtual reality(VR)and virtual globes–VR globes–enables users to not only view virtual scenes in an immersive manner at any location on Earth but also directly interact with multi-scale spatial da...The combination of virtual reality(VR)and virtual globes–VR globes–enables users to not only view virtual scenes in an immersive manner at any location on Earth but also directly interact with multi-scale spatial data using natural behaviors.It is an important direction for the future development of 3D GIS and geovisualization.However,current VR navigation are primarily based on small real spaces.For virtual globes,which are 3D multi-scale globe environment,the realization of VR navigation in the multi-scale virtual globe space within a limited real space is the first problem that needs to be addressed.A multi-scale VR navigation method that consists of two algorithms is proposed in this study.The first algorithm maps the real space to the virtual globe space and connects the VR user with the VR viewpoint.The second algorithm is an octree structure-based viewpoint correction algorithm that is proposed to correct the location of the moving VR viewpoint in real time.The proposed method is validated by experimentation.The experimental results indicate that the proposed method enables a VR user to interactively view the 3D multi-scale globe environment and lays a foundation for human–computer interaction in VR globes.展开更多
We address the registration problem of multisource three-dimensional(3D)human-made buildings with remote sensing images and the earth’s surface in the context of virtual globes.Challenges include fast transformation ...We address the registration problem of multisource three-dimensional(3D)human-made buildings with remote sensing images and the earth’s surface in the context of virtual globes.Challenges include fast transformation of 3D coordinates with different reference systems as well as the efficient use of original model information for rigorous and accurate model registration.This paper introduces a novel fast and scalable registration approach that can establish correspondences between heterogeneous external 3D city models and images/terrain surfaces of virtual globes in an efficient and accurate manner.The approach utilizes the projected 3D feature information of 3D city models to develop robust coordinate transformation and reliable model registration methods.The proposed approach builds a solid foundation for the fusion of multisource geospatial data in a united virtual globe reference framework.We report experimental results of online registration tasks for up to over 13K buildings in an integrated 3D virtual globe platform,namely,GeoGlobe.展开更多
The projections of climate change in the globe and East Asia by the NCC/IAPT63 model with the SRES A2 and A1B scenarios have been investigated in this paper. The resultspointed out a global warming of 3.6℃/100 yr and...The projections of climate change in the globe and East Asia by the NCC/IAPT63 model with the SRES A2 and A1B scenarios have been investigated in this paper. The resultspointed out a global warming of 3.6℃/100 yr and 2.5℃/100 yr for A2 and A1B during the 21stcentury, respectively. The warming in high and middle latitudes will be more obvious than that inlow latitudes, especially in the winter hemisphere. The warming of 5.1℃/100 yr for A2 and 3.6℃/100 yr for A1B over East Asia in the 21st century will be much higher than that in the globe. Theglobal mean precipitation will increase by about 4.3%/100 yr for A2 and 3.4%/100 yr for A1B in the21st century, respectively. The precipitation will increase in most parts of the low and highlatitudes and decrease in some regions of the subtropical latitudes. The linear trends of the annualmean precipitation anomalies over East Asia will be 9.8%/100 yr for A2 and 5.2%/100 yr for A1B,respectively. The drier situations will occur over the northwestern and southeastern parts of EastAsia. The changes of the annual mean temperature and precipitation in the globe for the 21st centuryby the NCC/IAP T63 model with SRES A2 and A1B scenarios are in agreement with a number of the modelprojections.展开更多
基金The Nature Science Foundation Innovation Group Project of Hubei Province,China[grant number 2016CFA003].
文摘The scene-rendering mechanism based on binocular vision is one of the key techniques for the VR globe to achieve immersion-type visualization of global 3D scenes.However,this special rendering mechanism also requires that the 3D scene is continuously drawn twice within one frame,which significantly affects the rendering efficiency of VR globes.Therefore,we propose a binocular parallel rendering method.This method first improves the current rendering process of VR globes by assigning the rendering tasks for the left and right camera of VR to be processed on different CPU cores,thereby achieving parallel rendering of binocular scenes.Second,due to the problem of inconsistent resolution of binocular scenes caused by different viewpoints for the left and right cameras,we propose a resolution synchronize algorithm.this algorithm conducts realtime synchronization on the resolution of scene in the rendering process and thus avoids the problem of erroneous binocular stereo matching.Finally,we validate the effectiveness of the method in this paper through experiments.The results of experiments indicate that while the method in this paper can ensure the consistency of binocular scene resolution,it can decrease the frame time of VR globes by approximately 27%on average.
文摘Science and policy increasingly request for sustainable development and growth.Similarly,Digital Earth undergoes a paradigm shift to an open platform that actively supports user engagement.While the public becomes able to contribute new content,we recognize a gap in user-driven validation,feedback and requirements capture,and innovative application development.Rather than defining Digital Earth applications top down,we see a need for methods and tools that will help building applications bottom up and driven by community needs.These should include a technology toolbox of geospatial and environ-mental enablers,which allow to access functional building blocks and content in multiple ways,but-equally important-enable the collaboration within partially unknown stakeholder networks.The validation and testing in real-life scenarios will be a central requirement when approaching the Digital Earth 2020 goals,which were articulated recently.We particularly argue to follow a Living Lab approach for co-creation and awareness rising in relation to environmental and geospatial matters.We explain why and how such a Digital Earth Living Lab could lead to a sustainable approach for developing,deploying,and using Digital Earth applications and suggest a paradigm shift for Virtual Globes becoming forums for research and innovation.
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.
基金This work was supported by National Key R&D Program of China:[grant number 2017YFB0503703]The Nature Science Foundation Innovation Group Project of Hubei Province,China:[grant number 2016CFA003].
文摘The combination of virtual reality(VR)and virtual globes–VR globes–enables users to not only view virtual scenes in an immersive manner at any location on Earth but also directly interact with multi-scale spatial data using natural behaviors.It is an important direction for the future development of 3D GIS and geovisualization.However,current VR navigation are primarily based on small real spaces.For virtual globes,which are 3D multi-scale globe environment,the realization of VR navigation in the multi-scale virtual globe space within a limited real space is the first problem that needs to be addressed.A multi-scale VR navigation method that consists of two algorithms is proposed in this study.The first algorithm maps the real space to the virtual globe space and connects the VR user with the VR viewpoint.The second algorithm is an octree structure-based viewpoint correction algorithm that is proposed to correct the location of the moving VR viewpoint in real time.The proposed method is validated by experimentation.The experimental results indicate that the proposed method enables a VR user to interactively view the 3D multi-scale globe environment and lays a foundation for human–computer interaction in VR globes.
基金This research was jointly supported by National Basic Research Program of China[No.2012CB719906]National Natural Science Foundation of China[No.41171314],[41023001],[41271400].
文摘We address the registration problem of multisource three-dimensional(3D)human-made buildings with remote sensing images and the earth’s surface in the context of virtual globes.Challenges include fast transformation of 3D coordinates with different reference systems as well as the efficient use of original model information for rigorous and accurate model registration.This paper introduces a novel fast and scalable registration approach that can establish correspondences between heterogeneous external 3D city models and images/terrain surfaces of virtual globes in an efficient and accurate manner.The approach utilizes the projected 3D feature information of 3D city models to develop robust coordinate transformation and reliable model registration methods.The proposed approach builds a solid foundation for the fusion of multisource geospatial data in a united virtual globe reference framework.We report experimental results of online registration tasks for up to over 13K buildings in an integrated 3D virtual globe platform,namely,GeoGlobe.
基金This research is supported by the IPCC-China Special Climate Projects and the Laboratory for Climate Studies of ChinaMeteorological Administration.
文摘The projections of climate change in the globe and East Asia by the NCC/IAPT63 model with the SRES A2 and A1B scenarios have been investigated in this paper. The resultspointed out a global warming of 3.6℃/100 yr and 2.5℃/100 yr for A2 and A1B during the 21stcentury, respectively. The warming in high and middle latitudes will be more obvious than that inlow latitudes, especially in the winter hemisphere. The warming of 5.1℃/100 yr for A2 and 3.6℃/100 yr for A1B over East Asia in the 21st century will be much higher than that in the globe. Theglobal mean precipitation will increase by about 4.3%/100 yr for A2 and 3.4%/100 yr for A1B in the21st century, respectively. The precipitation will increase in most parts of the low and highlatitudes and decrease in some regions of the subtropical latitudes. The linear trends of the annualmean precipitation anomalies over East Asia will be 9.8%/100 yr for A2 and 5.2%/100 yr for A1B,respectively. The drier situations will occur over the northwestern and southeastern parts of EastAsia. The changes of the annual mean temperature and precipitation in the globe for the 21st centuryby the NCC/IAP T63 model with SRES A2 and A1B scenarios are in agreement with a number of the modelprojections.
