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Central place indexing : hierarchical linear indexing systems for mixed-aperture hexagonal discrete global grid systems / Kevin Sahr in Cartographica, vol 54 n° 1 (Spring 2019)  

Public [article]  inCartographica > vol 54 n° 1 (Spring 2019) . - pp 16 - 29 Titre : Central place indexing : hierarchical linear indexing systems for mixed-aperture hexagonal discrete global grid systems Type de document : Article/Communication Auteurs : Kevin Sahr, Auteur Année de publication : 2019 Article en page(s) : pp 16 - 29 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique [Termes IGN] arbre quadratique [Termes IGN] indexation spatiale [Termes IGN] polyèdre [Termes IGN] système de grille globale discrète Résumé : (Auteur) Hexagonal discrete global grid systems (DGGSs) with integer spatial indexes are a promising new approach to designing geospatial data structures and location reference systems. Central place indexing (CPI) is a class of multi-precision hierarchical linear spatial indexing systems for pure and mixed-aperture hexagonal DGGSs. Definitions for CPI systems are given both on the plane and on the polyhedral surfaces of geodesic DGGSs, and examples of real-world DGGSs indexed using CPI are described. The semantic advantages of CPI systems are discussed, including their ability to exactly represent their own geometries. Numéro de notice : A2019-434 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3138/cart.54.1.2018-0022 Date de publication en ligne : 28/03/2019 En ligne : https://doi.org/10.3138/cart.54.1.2018-0022 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92760 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
031-2019011	SL	Revue	Centre de documentation	Revues en salle	Disponible

Spatial data management in apache spark: the GeoSpark perspective and beyond / Jia Yu in Geoinformatica, vol 23 n° 1 (January 2019)  

Public [article]  inGeoinformatica > vol 23 n° 1 (January 2019) . - pp 37 - 78 Titre : Spatial data management in apache spark: the GeoSpark perspective and beyond Type de document : Article/Communication Auteurs : Jia Yu, Auteur ; Zongsi Zhang, Auteur ; Mohamed Sarwat, Auteur Année de publication : 2019 Article en page(s) : pp 37 - 78 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées [Termes IGN] analyse comparative [Termes IGN] Apache (serveur) [Termes IGN] arbre k-d [Termes IGN] arbre quadratique [Termes IGN] arbre-R [Termes IGN] données massives [Termes IGN] Hadoop [Termes IGN] index spatial [Termes IGN] performance [Termes IGN] Spark [Termes IGN] traitement réparti Résumé : (auteur) The paper presents the details of designing and developing GeoSpark, which extends the core engine of Apache Spark and SparkSQL to support spatial data types, indexes, and geometrical operations at scale. The paper also gives a detailed analysis of the technical challenges and opportunities of extending Apache Spark to support state-of-the-art spatial data partitioning techniques: uniform grid, R-tree, Quad-Tree, and KDB-Tree. The paper also shows how building local spatial indexes, e.g., R-Tree or Quad-Tree, on each Spark data partition can speed up the local computation and hence decrease the overall runtime of the spatial analytics program. Furthermore, the paper introduces a comprehensive experiment analysis that surveys and experimentally evaluates the performance of running de-facto spatial operations like spatial range, spatial K-Nearest Neighbors (KNN), and spatial join queries in the Apache Spark ecosystem. Extensive experiments on real spatial datasets show that GeoSpark achieves up to two orders of magnitude faster run time performance than existing Hadoop-based systems and up to an order of magnitude faster performance than Spark-based systems. Numéro de notice : A2019-225 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s10707-018-0330-9 Date de publication en ligne : 22/10/2018 En ligne : http://dx.doi.org/10.1007/s10707-018-0330-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92621 [article]

Local curvature entropy-based 3D terrain representation using a comprehensive Quadtree / Giyu Chen in ISPRS Journal of photogrammetry and remote sensing, vol 139 (May 2018)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 139 (May 2018) . - pp 30 - 45 Titre : Local curvature entropy-based 3D terrain representation using a comprehensive Quadtree Type de document : Article/Communication Auteurs : Giyu Chen, Auteur ; Gang Liu, Auteur ; Xiaogang Ma, Auteur ; Gregoire Mariethoz, Auteur ; Zhenwen He, Auteur ; et al., Auteur Année de publication : 2018 Article en page(s) : pp 30 - 45 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] arbre quadratique [Termes IGN] entropie [Termes IGN] modèle numérique de terrain [Termes IGN] niveau de détail [Termes IGN] visualisation 3D Résumé : (Auteur) Large scale 3D digital terrain modeling is a crucial part of many real-time applications in geoinformatics. In recent years, the improved speed and precision in spatial data collection make the original terrain data more complex and bigger, which poses challenges for data management, visualization and analysis. In this work, we presented an effective and comprehensive 3D terrain representation based on local curvature entropy and a dynamic Quadtree. The Level-of-detail (LOD) models of significant terrain features were employed to generate hierarchical terrain surfaces. In order to reduce the radical changes of grid density between adjacent LODs, local entropy of terrain curvature was regarded as a measure of subdividing terrain grid cells. Then, an efficient approach was presented to eliminate the cracks among the different LODs by directly updating the Quadtree due to an edge-based structure proposed in this work. Furthermore, we utilized a threshold of local entropy stored in each parent node of this Quadtree to flexibly control the depth of the Quadtree and dynamically schedule large-scale LOD terrain. Several experiments were implemented to test the performance of the proposed method. The results demonstrate that our method can be applied to construct LOD 3D terrain models with good performance in terms of computational cost and the maintenance of terrain features. Our method has already been deployed in a geographic information system (GIS) for practical uses, and it is able to support the real-time dynamic scheduling of large scale terrain models more easily and efficiently. Numéro de notice : A2018-110 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2018.03.001 En ligne : https://doi.org/10.1016/j.isprsjprs.2018.03.001 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89540 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
081-2018051	RAB	Revue	Centre de documentation	En réserve L003	Disponible

A morphologically preserved multi-resolution TIN surface modeling and visualization method for virtual globes / Xianwei Zheng in ISPRS Journal of photogrammetry and remote sensing, vol 129 (July 2017)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 129 (July 2017) . - pp 41 - 54 Titre : A morphologically preserved multi-resolution TIN surface modeling and visualization method for virtual globes Type de document : Article/Communication Auteurs : Xianwei Zheng, Auteur ; Hanjiang Xiong, Auteur ; Jianya Gong, Auteur ; Linwei Yue, Auteur Année de publication : 2017 Article en page(s) : pp 41 - 54 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique web [Termes IGN] analyse multiéchelle [Termes IGN] arbre quadratique [Termes IGN] globe virtuel [Termes IGN] représentation cartographique 3D [Termes IGN] représentation du relief [Termes IGN] tessellation [Termes IGN] Triangulated Irregular Network Résumé : (Auteur) Virtual globes play an important role in representing three-dimensional models of the Earth. To extend the functioning of a virtual globe beyond that of a “geobrowser”, the accuracy of the geospatial data in the processing and representation should be of special concern for the scientific analysis and evaluation. In this study, we propose a method for the processing of large-scale terrain data for virtual globe visualization and analysis. The proposed method aims to construct a morphologically preserved multi-resolution triangulated irregular network (TIN) pyramid for virtual globes to accurately represent the landscape surface and simultaneously satisfy the demands of applications at different scales. By introducing cartographic principles, the TIN model in each layer is controlled with a data quality standard to formulize its level of detail generation. A point-additive algorithm is used to iteratively construct the multi-resolution TIN pyramid. The extracted landscape features are also incorporated to constrain the TIN structure, thus preserving the basic morphological shapes of the terrain surface at different levels. During the iterative construction process, the TIN in each layer is seamlessly partitioned based on a virtual node structure, and tiled with a global quadtree structure. Finally, an adaptive tessellation approach is adopted to eliminate terrain cracks in the real-time out-of-core spherical terrain rendering. The experiments undertaken in this study confirmed that the proposed method performs well in multi-resolution terrain representation, and produces high-quality underlying data that satisfy the demands of scientific analysis and evaluation. Numéro de notice : A2017-346 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2017.04.013 En ligne : https://dx.doi.org/10.1016/j.isprsjprs.2017.04.013 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85606 [article]

Exemplaires(3)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
081-2017071	RAB	Revue	Centre de documentation	En réserve L003	Disponible
081-2017073	DEP-EXM	Revue	LASTIG	Dépôt en unité	Exclu du prêt
081-2017072	DEP-EAF	Revue	Nancy	Dépôt en unité	Exclu du prêt

Variable-scale maps in real-time generalisation using a quadtree data structure and space deforming algorithms / Pia Bereuter in International journal of cartography, vol 3 n° 1 (June 2017)  

Public [article]  inInternational journal of cartography > vol 3 n° 1 (June 2017) . - pp 134 - 147 Titre : Variable-scale maps in real-time generalisation using a quadtree data structure and space deforming algorithms Type de document : Article/Communication Auteurs : Pia Bereuter, Auteur ; Robert Weibel, Auteur Année de publication : 2017 Article en page(s) : pp 134 - 147 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] arbre quadratique [Termes IGN] déformation géométrique [Termes IGN] généralisation à la volée [Termes IGN] généralisation automatique de données [Termes IGN] généralisation cartographique [Termes IGN] temps réel [Vedettes matières IGN] Généralisation Résumé : (Auteur) Variable-scale maps have been advocated by several authors in the context of mobile cartography. In the literature on real-time map generalisation, however, corresponding methods that resolve cartographic conflicts by deformation of the underlying map space together with the map foreground, are underrepresented. This paper demonstrates how the concept of a malleable space can be applied as a part of the generalisation process and incorporated into the overall methodology of point generalisation. Two different algorithms are used, a density-equalising cartogram algorithm and Laplacian smoothing. Both methods work in real-time and are datadriven. In addition, they allow for a parameterisation in combi-nation with a quadtree data structure, as well as a combination with 'classic' generalisation operators (e.g. selection, aggregation, displacement) based on the quadtree. The quadtree serves both as a spatial index for fast retrieval and search of points, and as a density estimator to inform generalisation operators. The use of the quadtree as a common spatial index provides a tool to combine variable-scale maps with classic generalisation. A combination of the two allows, at small map scales, the maintenance of detail in dense areas and data reduction in sparse areas. Additionally, it facilitates building a modular workflow for real-time map generalisation. Numéro de notice : A2017-322 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/23729333.2017.1304189 En ligne : http://dx.doi.org/10.1080/23729333.2017.1304189 Format de la ressource électronique : URL bulletin Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85380 [article]

Comparing image-based methods for assessing visual clutter in generalized maps / Guillaume Touya in ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, vol II-3 W5 (October 2015)  

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Real-time generalization of point data in mobile and web mapping using quadtrees / Pia Bereuter in Cartography and Geographic Information Science, vol 40 n° 4 (September 2013)  

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Comparison of different strategies for determining raster-based least-cost paths with a minimum amount of distortion / H. Antikainen in Transactions in GIS, vol 17 n° 1 (February 2013)  

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Vers une nouvelle prise en compte de l'esthétique dans la composition de la carte thématique : propositions de méthodes et d'outils / Laurent Jégou (2013)  

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Visualisation 3D de terrain texturé : préservation au niveau du pixel des qualités géométriques et colorimétriques, une méthode temps réel, innovante et simple / T.V. Lê in Revue internationale de géomatique, vol 22 n° 3 (septembre - novembre 2012)  

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An interactive framework for spatial joins : a statistical approach to data analysis in GIS / S. Alkobaisi in Geoinformatica, vol 16 n° 2 (April 2012)  

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Equal arc ratio projection and a new spherical triangle quadtree model / Y. Wen in International journal of geographical information science IJGIS, vol 24 n°11-12 (december 2010)  

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Perfectionnement du moteur de rendu 3D des données géographiques de la société Realitymaps / Adrien Chassard (2009)

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Capture de layers durant une session dans un globe virtuel / G. Mazabraud (2008)

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Weight-proportional space partitioning using adaptative Voronoi diagrams / R. Reitsma in Geoinformatica, vol 11 n° 3 (September - November 2007)  

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