Centre de documentation
scientifique

Dépouillements

Complex spatial query processing / Nikos Mamoulis in Geoinformatica, vol 8 n° 4 (December 2004)  

Public [article]  inGeoinformatica > vol 8 n° 4 (December 2004) . - pp 311 - 346 Titre : Complex spatial query processing Type de document : Article/Communication Auteurs : Nikos Mamoulis, Auteur ; Dimitris Papadias, Auteur ; D. Arkoumanis, Auteur Année de publication : 2004 Article en page(s) : pp 311 - 346 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées [Termes IGN] base de données localisées [Termes IGN] jointure spatiale [Termes IGN] optimisation (mathématiques) [Termes IGN] requête spatiale Résumé : (Auteur) The user of a Geographical Information System is not limited to conventional spatial selections and joins, but may also pose more complicated and descriptive queries. In this paper, we focus on the efficient processing and optimization of complex spatial queries that involve combinations of spatial selections and joins. Our contribution is manifold; we first provide formulae that accurately estimate the selectivity of such queries. These formulae, paired with cost models for selections and joins can be used to combine spatial operators in an optimal way. Second, we propose algorithms that process spatial joins and selections simultaneously and are typically more efficient than combinations of simple operators. Finally we study the problem of optimizing complex spatial queries using these operators, by providing (i) cost models, and (ii) rules that reduce the optimization space significantly. The accuracy of the selectivity models and the efficiency of the proposed algorithms are evaluated through experimentation. Numéro de notice : A2004-391 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1023/B:GEIN.0000040830.73424.f0 En ligne : https://doi.org/10.1023/B:GEIN.0000040830.73424.f0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26918 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
057-04041	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Defining and comparing content measures of topological relations / F. Godoy in Geoinformatica, vol 8 n° 4 (December 2004)  

Public [article]  inGeoinformatica > vol 8 n° 4 (December 2004) . - pp 347 - 371 Titre : Defining and comparing content measures of topological relations Type de document : Article/Communication Auteurs : F. Godoy, Auteur ; A. Rodriguez, Auteur Année de publication : 2004 Article en page(s) : pp 347 - 371 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées [Termes IGN] analyse comparative [Termes IGN] rectangle englobant minimum [Termes IGN] relation topologique Résumé : (Auteur) This work defines and compares three quantitative content measures of topological relations between spatial objects that consider metric refinements with respect to relative size, distance, and degree of overlapping. These content measures use minimum bounding rectangles (MBRs) as simplified views of spatial objects in order to create an efficient mechanism for characterizing the topological content of spatial configurations. A framework for comparing content measures is presented, which is based on the linear correlation between two similarity rankings : (1) a similarity ranking defined in terms of the distance of content-measure values and (2) a similarity ranking defined in terms of the error of the geometric adjustment between pairs of objects. The linear correlation between similarity rankings is used as indicator of how well the defined content measures characterize topological relations. Such kind of content measures can provide mechanisms for creating efficient methods to describe and access information on the basis of the topological content of spatial configurations. Numéro de notice : A2004-392 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1023/B:GEIN.0000040831.81391.1d En ligne : https://doi.org/10.1023/B:GEIN.0000040831.81391.1d Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26919 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
057-04041	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Multi-way distance joins queries in spatial databases / A. Corral in Geoinformatica, vol 8 n° 4 (December 2004)  

Public [article]  inGeoinformatica > vol 8 n° 4 (December 2004) . - pp 373 - 402 Titre : Multi-way distance joins queries in spatial databases Type de document : Article/Communication Auteurs : A. Corral, Auteur ; Y. Manolopoulos, Auteur ; Y. Theodoridis, Auteur ; M. Vassilakopoulos, Auteur Année de publication : 2004 Article en page(s) : pp 373 - 402 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] graphe [Termes IGN] jointure spatiale [Termes IGN] requête spatiale Résumé : (Auteur) Let a tuple of n objects obeying a query graph (QG) be called the n-tuple. The "Ddistance-value" of this n-tuple is the value of a linear function of distances of the n objects that make up this n-tuple, according to the edges of the QG. This paper addresses the problem of finding the K n-tuples between n spatial datasets that have the smallest Ddistance-values, the so-called K-multi-way distance join query (K-MWDJQ), where each set is indexed by an R-tree-based structure. This query can be viewed as an extension of K-closest-pairs query (K-CPQ) for n inputs. In addition, a recursive non-incremental branch-and-bound algorithm following a depth-first search for processing synchronously all inputs without producing any intermediate result is proposed. Enhanced pruning techniques are also applied to n R-trees nodes in order to reduce the total response time and the number of distance computations of the query. Due to the exponential nature of the problem, we also propose a time-based approximate version of the recursive algorithm that combines approximation techniques to adjust the quality of the result and the global processing time. Finally, we give a detailed experimental study of the proposed algorithms using real spatial datasets, highlighting their performance and the quality of the approximate results. Numéro de notice : A2004-393 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1023/B:GEIN.0000040832.25622.8d En ligne : https://doi.org/10.1023/B:GEIN.0000040832.25622.8d Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26920 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
057-04041	RAB	Revue	Centre de documentation	En réserve L003	Disponible