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Centrality-based hierarchy for street network generalization in multi-resolution maps / Wasim Shoman in Geocarto international, vol 32 n° 12 (December 2017)
[article]
Titre : Centrality-based hierarchy for street network generalization in multi-resolution maps Type de document : Article/Communication Auteurs : Wasim Shoman, Auteur ; Fatih Gülgen, Auteur Année de publication : 2017 Article en page(s) : pp 1352 - 1366 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] axe médian
[Termes IGN] base de données multi-représentation
[Termes IGN] extraction de traits caractéristiques
[Termes IGN] généralisation automatique de données
[Termes IGN] graphe
[Termes IGN] processus de hiérarchisation analytique floue
[Termes IGN] réseau routier
[Termes IGN] route
[Termes IGN] zoom
[Vedettes matières IGN] GénéralisationRésumé : (Auteur) This paper introduces a new hierarchy for cartographic generalisation processes, applied in street networks. The aims of implementing this hierarchy are to emphasise on significant street features, and to provide more free spaces between street features. The hierarchy is obtained from the functional classes of the features and four centrality measures in a street network, i.e. betweenness, reach, straightness and closeness extracted from a primary graph. The values of centrality measures change in every zoom level by calculating a radius parameter, which depends on the users’ field of view. The coefficients for the measures are constructed using a decision-making technique called fuzzy analytical hierarchy process (FAHP). The weights for each of the centrality measures are computed and normalised to form the proposed hierarchy. The hierarchy is applied and used later in the thinning process to omit insignificant features from the street network in medium scales. Numéro de notice : A2017-673 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10106049.2016.1208683 En ligne : https://doi.org/10.1080/10106049.2016.1208683 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=87164
in Geocarto international > vol 32 n° 12 (December 2017) . - pp 1352 - 1366[article]Cut Pursuit: Fast algorithms to learn piecewise constant functions on general weighted graphs / Loïc Landrieu in SIAM Journal on Imaging Sciences, vol 10 n° 4 (November 2017)
[article]
Titre : Cut Pursuit: Fast algorithms to learn piecewise constant functions on general weighted graphs Type de document : Article/Communication Auteurs : Loïc Landrieu , Auteur ; Guillaume Obozinski, Auteur Année de publication : 2017 Projets : 2-Pas d'info accessible - article non ouvert / Article en page(s) : pp 1724 - 1766 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] algorithme Cut Pursuit
[Termes IGN] graphe
[Termes IGN] pondérationRésumé : (auteur) We propose working set/greedy algorithms to efficiently solve problems penalized, respectively, by the total variation on a general weighted graph and its $\ell_0$ counterpart the total level-set boundary size when the piecewise constant solutions have a small number of distinct level sets; this is typically the case when the total level-set boundary size is small, which is encouraged by these two forms of penalization. Our algorithms exploit this structure by recursively splitting the level sets of a piecewise constant candidate solution using graph cuts. We obtain significant speedups over state-of-the-art algorithms for images that are well approximated with few level sets. Numéro de notice : A2017-891 Affiliation des auteurs : LASTIG MATIS+Ext (2012-2019) Thématique : IMAGERIE/MATHEMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1137/17M1113436 Date de publication en ligne : 10/10/2017 En ligne : https://doi.org/10.1137/17M1113436 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91884
in SIAM Journal on Imaging Sciences > vol 10 n° 4 (November 2017) . - pp 1724 - 1766[article]Hub Labels on the database for large-scale graphs with the COLD framework / Alexandros Efentakis in Geoinformatica, vol 21 n° 4 (October - December 2017)
[article]
Titre : Hub Labels on the database for large-scale graphs with the COLD framework Type de document : Article/Communication Auteurs : Alexandros Efentakis, Auteur ; Christodoulos Efstathiades, Auteur ; Dieter Pfoser, Auteur Année de publication : 2017 Article en page(s) : pp 703 - 732 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale
[Termes IGN] base de données localisées
[Termes IGN] chemin le plus court, algorithme du
[Termes IGN] compression de données
[Termes IGN] graphe
[Termes IGN] plus proche voisin, algorithme du
[Termes IGN] SQLRésumé : (Auteur) Shortest-path computation on graphs is one of the most well-studied problems in algorithmic theory. An aspect that has only recently attracted attention is the use of databases in combination with graph algorithms, so-called distance oracles, to compute shortest-path queries on large graphs. To this purpose, we propose a novel, efficient, pure-SQL framework for answering exact distance queries on large-scale graphs, implemented entirely on an open-source database engine. Our COLD framework (COmpressed Labels on the Database) can answer multiple distance queries (vertex-to-vertex, one-to-many, k-Nearest Neighbors, Reverse k-Nearest Neighbors, Reverse k-Farthest Neighbors and Top-k Range) not handled by previous methods, rendering it a complete database solution for a variety of practical large-scale graph applications. Our experimentation shows that COLD outperforms existing approaches (including popular graph databases) in terms of query time and efficiency, while requiring significantly less storage space than these methods. Numéro de notice : A2017-601 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1007/s10707-016-0287-5 En ligne : https://doi.org/10.1007/s10707-016-0287-5 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86909
in Geoinformatica > vol 21 n° 4 (October - December 2017) . - pp 703 - 732[article]Uncertain Voronoi cell computation based on space decomposition / Klaus Arthur Schmid in Geoinformatica, vol 21 n° 4 (October - December 2017)
[article]
Titre : Uncertain Voronoi cell computation based on space decomposition Type de document : Article/Communication Auteurs : Klaus Arthur Schmid, Auteur ; Andreas Züfle, Auteur ; Tobias Emrich, Auteur ; et al., Auteur Année de publication : 2017 Article en page(s) : pp 763 -795 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale
[Termes IGN] décomposition spatiale
[Termes IGN] diagramme de Voronoï
[Termes IGN] incertitude des données
[Termes IGN] plus proche voisin, algorithme du
[Termes IGN] traitement parallèleRésumé : (Auteur) To facilitate (k)-Nearest Neighbor queries, the concept of Voronoi decomposition is widely used. In this work, we propose solutions to extend the concept of Voronoi-cells to uncertain data. Due to data uncertainty, the location, the shape and the extent of a Voronoi cell are random variables. To facilitate reliable query processing despite the presence of uncertainty, we employ the concept of possible-Voronoi cells and introduce the novel concept of guaranteed-Voronoi cells: The possible-Voronoi cell of an object U consists of all points in space that have a non-zero probability of having U as their nearest-neighbor; and the guaranteed-Voronoi cell, which consists of all points in space which must have U as their nearest-neighbor. Since exact computation of both types of Voronoi cells is computationally hard, we propose approximate solutions. Therefore, we employ hierarchical access methods for both data and object space. Our proposed algorithm descends both index structures simultaneously, constantly trying to prune branches in both trees by employing the concept of spatial domination. To support (k)-Nearest Neighbor queries having k > 1, this work further pioneers solutions towards the computation of higher-order possible and higher-order guaranteed Voronoi cells, which consist of all points in space which may (respectively must) have U as one of their k-nearest neighbors. For this purpose, we develop three algorithms to explore our index structures and show that the approach that descends both index structures in parallel yields the fastest query processing times. Our experiments show that we are able to approximate uncertain Voronoi cells of any order much more effectively than the state-of-the-art while improving run-time performance. Since our approach is the first to compute guaranteed-Voronoi cells and higher order (possible and guaranteed) Voronoi cells, we extend the existing state-of-the-art solutions to these concepts, in order to allow a fair experimental evaluation. Numéro de notice : A2017-604 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1007/s10707-017-0293-2 En ligne : https://doi.org/10.1007/s10707-017-0293-2 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86913
in Geoinformatica > vol 21 n° 4 (October - December 2017) . - pp 763 -795[article]Exploiting illusory grid lines for object-location memory performance in urban topographic maps / Frank Dickmann in Cartographic journal (the), Vol 54 n° 3 (August 2017)
[article]
Titre : Exploiting illusory grid lines for object-location memory performance in urban topographic maps Type de document : Article/Communication Auteurs : Frank Dickmann, Auteur ; Dennis Edler, Auteur ; Anne-Kathrin Bestgen, Auteur ; Lars Kuchinke, Auteur Année de publication : 2017 Article en page(s) : pp 242-253 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cartographie
[Termes IGN] carte interactive
[Termes IGN] carte topographique
[Termes IGN] géopositionnement
[Termes IGN] quadrillage
[Termes IGN] symbole graphique
[Termes IGN] système d'information géographique
[Termes IGN] topologieRésumé : (Auteur) In order to be successful in spatial orientation tasks, people need to recall locations and configurations of spatial objects from their memory. This understanding of geographic space often arises from experience with cartographic media representing topographic and topological information by graphic symbols. Learning spatial information from graphic media is influenced by different perception-based grouping effects distorting the accuracy of spatial object-positions and their relations. Such geometric inaccuracies can be softened by adding a grid layer, which regionalizes the map and can be used as an additional orientation pattern. This grid layer usually consists of solid lines and overlays semantic information. The present paper reports the results of two empirical studies on object-location memory (OLM) performance. In these studies, the amount of visual detail of the grid layer was reduced. By positioning the grid layer below specific urban topographic objects (study 1), the grid pattern was graphically interrupted. These interrupted grid lines were completed by cognitive completion mechanisms (illusory grid lines) described in the Gestalt principles of closure and continuation. The second experiment examined the maximum grid line gap that is closed by cognitive line completion and keeps an advantage for OLM (study 2). Numéro de notice : A2017-693 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00087041.2016.1236509 En ligne : https://doi.org/10.1080/00087041.2016.1236509 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=88003
in Cartographic journal (the) > Vol 54 n° 3 (August 2017) . - pp 242-253[article]Réservation
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