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The largest empty rectangle containing only a query object in Spatial Databases / Gilberto Gutiérrez in Geoinformatica, vol 18 n° 2 (April 2014)  

Public [article]  inGeoinformatica > vol 18 n° 2 (April 2014) . - pp 193 - 228 Titre : The largest empty rectangle containing only a query object in Spatial Databases Type de document : Article/Communication Auteurs : Gilberto Gutiérrez, Auteur ; José R. Paramá, Auteur ; Nieves Brisaboa, Auteur ; Antonio Corral, Auteur Année de publication : 2014 Article en page(s) : pp 193 - 228 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées [Termes IGN] arbre-R [Termes IGN] base de données localisées [Termes IGN] classification automatique d'objets [Termes IGN] indexation spatiale [Termes IGN] requête spatiale [Termes IGN] traitement automatique de données Résumé : (Auteur) Let S be a set of n points in a fixed axis-parallel rectangle R Í R2 , i.e. in the two-dimensional space (2D). Assuming that those points are stored in an R-tree, this paper presents several algorithms for finding the empty rectangle in R with the largest area, sides parallel to the axes of the space, and containing only a query point q. This point can not be part of S, that is, it is not stored in the R-tree. All algorithms follow the basic idea of discarding part of the points of S, in such a way that the problem can be solved only considering the remaining points. As a consequence, the algorithms only have to access a very small portion of the nodes (disk blocks) of the R-tree, saving main memory resources and computation time. We provide formal proofs of the correctness of our algorithms and, in order to evaluate the performance of the algorithms, we run an extensive set of experiments using synthetic and real data. The results have demonstrated the efficiency and scalability of our algorithms for different dataset configurations. Numéro de notice : A2014-224 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1007/s10707-013-0178-y Date de publication en ligne : 19/04/2013 En ligne : https://doi.org/10.1007/s10707-013-0178-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=33127 [article]

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The k closest pairs in spatial databases: When only set is indexed / Gilberto Gutiérrez in Geoinformatica, vol 17 n° 4 (October 2013)  

Public [article]  inGeoinformatica > vol 17 n° 4 (October 2013) . - pp 543 - 565 Titre : The k closest pairs in spatial databases: When only set is indexed Type de document : Article/Communication Auteurs : Gilberto Gutiérrez, Auteur ; Pablo Saez, Auteur Année de publication : 2013 Article en page(s) : pp 543 - 565 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées [Termes IGN] arbre-R [Termes IGN] base de données localisées [Termes IGN] extensibilité [Termes IGN] rectangle englobant minimum [Termes IGN] requête spatiale Résumé : (Auteur) We provide in this article a branch-and-bound algorithm that solves the problem of finding the k closest pairs of points (p,q), p € P,q € Q, considering two sets of points in the euclidean plane P,Q stored in external memory assuming that only one of the sets has a spatial index. This problem arises naturally in many scenarios, for instance when the set without an index is the answer to a spatial query. The main idea of our algorithm is to partition the space occupied by the set without an index into several cells or subspaces and to make use of the properties of a set of metrics defined on two Minimum Bounding Rectangles (MBRs). We evaluated our algorithm for different values of k by means of a series of experiments that considered both synthetical and real world datasets. We compared the performance of our algorithm with that of techniques that either assume that both datasets have a spatial index or that none has an index. The results show that our algorithm needs only between a 0.3 and a 35 % of the disk accesses required by such techniques. Our algorithm also shows a good scalability, both in terms of k and of the size of the data set. Numéro de notice : A2013-509 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1007/s10707-012-0169-4 Date de publication en ligne : 14/09/2012 En ligne : https://doi.org/10.1007/s10707-012-0169-4 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32647 [article]

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Code-barres	Cote	Support	Localisation	Section	Disponibilité
057-2013041	RAB	Revue	Centre de documentation	En réserve L003	Disponible