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A topographically preserved road‐network tile model and optimal routing method for virtual globes / Quanhua Dong in Transactions in GIS, vol 23 n° 2 (April 2019)  

Public [article]  inTransactions in GIS > vol 23 n° 2 (April 2019) . - pp 294 - 311 Titre : A topographically preserved road‐network tile model and optimal routing method for virtual globes Type de document : Article/Communication Auteurs : Quanhua Dong, Auteur ; Jing Chen, Auteur ; Tingting Liu, Auteur Année de publication : 2019 Article en page(s) : pp 294 - 311 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique web [Termes descripteurs IGN] calcul d'itinéraire [Termes descripteurs IGN] chemin le plus court (algorithme) [Termes descripteurs IGN] globe virtuel [Termes descripteurs IGN] intégrité topologique [Termes descripteurs IGN] réseau routier Résumé : (Auteur) Virtual globes enable the combination of heterogeneous datasets for optimal routing analyses in transportation, environmental ecology, and construction engineering. In this study, considering the advantages of the hierarchical tiling structure and topography of virtual globes, we propose a tile‐based optimal routing method for large‐scale road networks in a virtual globe. This method designs a topographically preserved road‐network tile model by partitioning roads into tiles and constructs the road‐network pyramid from the bottom to the top. During construction, a TileArc is calculated and flagged as the shortest path in a tile. Based on the built road‐network pyramid carrying hierarchical TileArcs, a multi‐level and flexible shortest path query can be executed efficiently. The proposed method is implemented with large road networks with different road grades in a virtual globe. Experimental results verify its validity, efficiency, and exactness. Moreover, the length of the shortest path with surface distance is approximately 1.3 times longer than that with Euclidean distance. Numéro de notice : A2019-252 Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12520 date de publication en ligne : 13/01/2019 En ligne : https://doi.org/10.1111/tgis.12520 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93010 [article]

A virtual globe-oriented visualization method for 3D meteorological fields / Jing Chen in Geomatics and Information Science of Wuhan University, vol 41 n° 12 (December 2016)  

Public [article]  inGeomatics and Information Science of Wuhan University > vol 41 n° 12 (December 2016) Titre : A virtual globe-oriented visualization method for 3D meteorological fields Type de document : Article/Communication Auteurs : Jing Chen, Auteur ; Cheng Zou, Auteur ; Wumeng Huang, Auteur ; Boyang Liu, Auteur Année de publication : 2016 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes descripteurs IGN] données localisées 3D [Termes descripteurs IGN] données météorologiques [Termes descripteurs IGN] globe virtuel [Termes descripteurs IGN] requête spatiotemporelle [Termes descripteurs IGN] visualisation de données [Termes descripteurs IGN] voxel [Vedettes matières IGN] Géovisualisation Résumé : (auteur) Meteorological fields represent a multidimensional dynamic environment; therefore visualization is a means study inherent regularities in these phenomena. In this paper, aiming to visualize the worldwide, multi-dimensional, multi-scale, massive characteristics of meteorological field data, a voxel object-oriented data model and a voxel based multi-level indexing mechanism were designed. A visualization method for 3D meteorological fields is proposed, including an arrow model based visualization method for vector fields and improved 3D texture-mapping based volume rendering method for scalar fields. Visualization and spatio-temporal retrieval experiments on a Virtual Globe platform were carried out to demonstrate the feasibility and effectiveness of the proposed methods. Numéro de notice : A2016--123 Thématique : GEOMATIQUE Nature : Article En ligne : http://ch.whu.edu.cn/EN/10.13203/j.whugis20140520 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=84962 [article]

Progressive visualization of complex 3D models over the internet / Jing Chen in Transactions in GIS, vol 20 n° 6 (December 2016)  

Public [article]  inTransactions in GIS > vol 20 n° 6 (December 2016) . - pp 887 - 902 Titre : Progressive visualization of complex 3D models over the internet Type de document : Article/Communication Auteurs : Jing Chen, Auteur ; Jiawei Li, Auteur ; Mo Li, Auteur Année de publication : 2016 Article en page(s) : pp 887 - 902 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes descripteurs IGN] données maillées [Termes descripteurs IGN] données multiéchelles [Termes descripteurs IGN] image numérique [Termes descripteurs IGN] niveau de détail [Termes descripteurs IGN] rendu automatisé [Termes descripteurs IGN] simulation 3D [Termes descripteurs IGN] Web 3D Service [Vedettes matières IGN] Géovisualisation Résumé : (auteur) The online transmission and real-time rendering of complex 3D models have always been a bottleneck which limits the performance of Web 3D simulation systems. To improve the efficiency of data transmission and mesh reconstruction, this article proposes a novel progressive mesh structure. In the first stage of progressive visualization, the base data and the base index generated by vertex clustering simplification are transmitted to the client for the fundamental rendering. Then the incremental data and corresponding indexes at higher levels are transmitted, as the viewpoint approaches the simulation object. The multi-scale incremental data organization benefits the performance and efficiency of the Web 3D simulation system by separately transmitting and reconstructing the corresponding level of mesh details. To demonstrate the adaptability and reliability of this algorithm, we developed an experimental prototype system to conduct a series of experiments. The results of experiments show that the improved progressive mesh structure described in this article takes good advantage of the vertex clustering simplification scheme to increase the efficiency of online transmission and mesh reconstruction, and the average frame rate of the progressive visualization has been increased to some extent, especially for massive data in large scale scenes. Numéro de notice : A2016-996 Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern En ligne : http://dx.doi.org/10.1111/tgis.12185 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83776 [article]

Rendering interior-filled polygonal vector data in a virtual globe / Mengyun Zhou in International journal of geographical information science IJGIS, vol 30 n° 11-12 (November - December 2016)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 30 n° 11-12 (November - December 2016) . - pp 2208 - 2229 Titre : Rendering interior-filled polygonal vector data in a virtual globe Type de document : Article/Communication Auteurs : Mengyun Zhou, Auteur ; Jing Chen, Auteur ; Jianya Gong, Auteur Année de publication : 2016 Article en page(s) : pp 2208 - 2229 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes descripteurs IGN] données vectorielles [Termes descripteurs IGN] Global Multi-resolution Terrain Elevation Data 2010 [Termes descripteurs IGN] globe virtuel [Termes descripteurs IGN] modèle numérique de surface [Termes descripteurs IGN] modélisation 3D [Termes descripteurs IGN] polygone [Termes descripteurs IGN] rendu (géovisualisation) [Termes descripteurs IGN] temps réel [Vedettes matières IGN] Géovisualisation Résumé : (Auteur) Polygonal vector data are important for representing countries, lakes, residential settlements, and other polygonal features. The proper representation of polygonal vector data is the basis of efficient rendering and picking and quick access and display of the analysis results based on polygons (e.g., 3D overlaying and surface area measurement in mountainous areas) in a virtual globe. However, polygonal vector data are displayed using texture-based or boundary-based approaches in most existing virtual globes. The texture-based approach cannot easily support interactive operations (e.g., picking) and spatial analysis (e.g., adjacency analysis and spatial measurement). The boundary-based approach treats the holes as independent features; however, it is difficult to recognize which boundaries constitute a polygon. Further research is needed on how to better organize the polygons to support efficient rendering, picking, and analysis in a virtual globe. In this article, we propose two methods to drape interior filled 2D polygons onto a multi-resolution 3D terrain. Both proposed methods combine polygon clipping and polygon triangulation. The difference between the two methods is in the way holes are eliminated. Method 1 recursively subdivides a terrain triangle until the child-triangles contain no holes; every resulting clipped polygon, which is then triangulated, contains no holes. Method 2 directly clips a polygon against a terrain triangle and creates bridge edges to transform the resulting polygons with holes to degenerate polygons that are further triangulated. The experimental results demonstrate that both proposed methods can efficiently process polygons with holes resulting in appropriate numbers of triangles. The processed interior-filled polygons remain close to the terrain surface in a virtual globe. Both proposed methods support real-time rendering of polygonal vector data in a virtual globe. Numéro de notice : A2016-751 Thématique : GEOMATIQUE/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/13658816.2016.1165819 En ligne : http://dx.doi.org/10.1080/13658816.2016.1165819 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82340 [article]

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Fast construction of global pyramids for very large satellite images / Longgang Xiang in Transactions in GIS, vol 17 n° 2 (April 2013)  

Public [article]  inTransactions in GIS > vol 17 n° 2 (April 2013) . - pp 282 - 297 Titre : Fast construction of global pyramids for very large satellite images Type de document : Article/Communication Auteurs : Longgang Xiang, Auteur ; Jing Chen, Auteur ; Jianya Gong, Auteur ; Zhen Zeng, Auteur Année de publication : 2013 Article en page(s) : pp 282 - 297 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes descripteurs IGN] données multiéchelles [Termes descripteurs IGN] globe virtuel [Termes descripteurs IGN] image satellite [Termes descripteurs IGN] mise à l'échelle Résumé : (Auteur) Satellite imagery plays a critical role in recent popular Virtual Globe systems since it delivers spatially-related information in a direct and intuitive way. A satellite image may be very large in size due to large coverage, high resolution, or both, and therefore the construction of global pyramids, a core data structure of Virtual Globe, will be time-consuming if designed improperly. This article, based on the idea of divide-and-conquer, proposes an efficient algorithm, termed CGP, for the Construction of Global Pyramids, which builds global pyramids with only a single sequential scan of input imagery. By analyzing the space complexity of CGP, the memory-minimum pyramid level is derived, at which the memory requirement of CGP is minimized to a practical level, even for very large satellite images. This article also discusses a parallel implementation of CGP, which parallelizes the two main actions in CGP, thus further improving the pyramid construction performance. Both theoretical analysis and experimental results show that our approach outperforms other methods and, more importantly, this advantage increases considerably as the size of input imagery increases. Numéro de notice : A2013-175 Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12001 date de publication en ligne : 05/10/2012 En ligne : https://doi.org/10.1111/tgis.12001 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32313 [article]

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