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Merging R-trees: efficient strategies for local bulk insertion / L. Chen in Geoinformatica, vol 6 n° 1 (March - May 2002)  

Public [article]  inGeoinformatica > vol 6 n° 1 (March - May 2002) . - pp 7 - 34 Titre : Merging R-trees: efficient strategies for local bulk insertion Type de document : Article/Communication Auteurs : L. Chen, Auteur ; R. Choubey, Auteur ; E.A. Rundensteiner, Auteur Année de publication : 2002 Article en page(s) : pp 7 - 34 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées [Termes IGN] arbre-R [Termes IGN] index spatial [Termes IGN] indexation spatiale [Termes IGN] intégration de données [Termes IGN] jeu de données localisées [Termes IGN] requête spatiale Résumé : (Auteur) A lot of recent work has focussed on bulk loading of data into multidimensional index structures in order to efficiently construct such structures for large data sets. In this paper, we address this problem with particular focus on R-trees - which are an important class of index structures used widely in commercial database systems. We propose a new technique, which as opposed to the current technique of inserting data one by one, bulk inserts entire new data sets into an active R-tree. This technique, called STLT (for small-tree-large-tree), considers the new data set as an R-tree itself (small tree), identifies and prepares a suitable location in the original R-tree (large tree) for insertion, and lastly performs the insert of the small tree into the large tree. Besides an analytical cost model of STLT, extensive experimental studies both on synthetic and real GIS data sets are also reported. These experiments not only compare STLT against the conventional technique, but also evaluate the suitability and limitations of STLT under different conditions, such as varying buffer sizes, ratio between existing and new data sizes, and skewness of new data with respect to the whole spatial region. We find that STLT does much better (in average, about 65%) than the existing technique for skewed data sets as well for large sizes of both the large tree and the small tree in terms of insertion time, while keeping comparable query tree quality. STLT consistently outperforms the alternate technique in all other circumstances in terms of bulk insertion time, especially, even up to 2,000% for the cases when the area of new data sets covers up to 4% of the global region covered by the existing index tree; however, at the cost of a deteriorating resulting tree quality. Numéro de notice : A2002-107 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1023/A:1013764014000 En ligne : https://doi.org/10.1023/A:1013764014000 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22022 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
057-02011	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Generalized model for linear referencing in transportation / P. Scarponcini in Geoinformatica, vol 6 n° 1 (March - May 2002)  

Public [article]  inGeoinformatica > vol 6 n° 1 (March - May 2002) . - pp 35 - 55 Titre : Generalized model for linear referencing in transportation Type de document : Article/Communication Auteurs : P. Scarponcini, Auteur Année de publication : 2002 Article en page(s) : pp 35 - 55 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées [Termes IGN] base de données routières [Termes IGN] modèle conceptuel de données [Termes IGN] système d'information géographique [Termes IGN] système d'information routière [Termes IGN] transport routier Résumé : (Auteur) The Generalized Model for Linear Referencing is proposed as a theoretical basis for representing and translating linear locations. It separates the concepts of the linear element which is being measured and the linear method of measurement. It formalizes the concept of a distance expression as the measurement which is made. A location expression is then introduced as the combination of these three concepts. Comprised of mappings between location expressions, a generalized set of translation expressions are formalized as the method of converting between measurement methods and linear elements. Numéro de notice : A2002-108 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1023/A:1013716130838 En ligne : https://doi.org/10.1023/A:1013716130838 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22023 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
057-02011	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Dual grid: a new approach for robust spatial algebra implementation / J.A. Cotelo Lema in Geoinformatica, vol 6 n° 1 (March - May 2002)  

Public [article]  inGeoinformatica > vol 6 n° 1 (March - May 2002) . - pp 57 - 76 Titre : Dual grid: a new approach for robust spatial algebra implementation Type de document : Article/Communication Auteurs : J.A. Cotelo Lema, Auteur ; Ralf Hartmut Güting, Auteur Année de publication : 2002 Article en page(s) : pp 57 - 76 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes d'information géographique [Termes IGN] base de données localisées [Termes IGN] implémentation (informatique) [Termes IGN] intégrité topologique [Termes IGN] méthode robuste [Termes IGN] modèle conceptuel de données localisées Résumé : (Auteur) Systems of spatial data types and operations, or spatial algebras, are fundamental for the implementation of spatial database systems. Several designs of such algebras have been proposed in the last decade, and recently commercial DBMS offer such algebras in the form of extension packages (e.g., “data blades"). However, actual implementations are generally severely restricted when compared to designs in the literature. A main reason is that at the implementation level one cannot further ignore the problems of robustness and topological correctness arising from the discrete number representations used in computers. Therefore, implemented packages either avoid problematic operations, or accept inconsistencies and topological errors in the answers of queries due to rounding effects. The ROSE algebra, proposed and implemented earlier, goes a long way towards avoiding such problems, since it was defined from scratch with robustness problems in mind. It is founded on a discrete geometric basis called a realm. The ROSE algebra guarantees a correct behaviour of operations and has an entirely robust implementation. Unfortunately, the realm concept and its interaction with DBMS are difficult to implement, and certain kinds of topological problems still remain. In this paper we introduce the concept of dual grid, which provides a new approach for the representation of spatial information that avoids any robustness and topological correctness problem and allows a less restrictive implementation of spatial algebras. As an example, we show how can it be used for implementing the ROSE algebra without realms, and show that such an implementation does not suffer from the side effects and disadvantages of the original realm-based one. Numéro de notice : A2002-109 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1023/A:1013768114909 En ligne : https://doi.org/10.1023/A:1013768114909 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22024 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
057-02011	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Tabu search heuristic for point-feature cartographic label placement / M. Yamamoto in Geoinformatica, vol 6 n° 1 (March - May 2002)  

Public [article]  inGeoinformatica > vol 6 n° 1 (March - May 2002) . - pp 77 - 90 Titre : Tabu search heuristic for point-feature cartographic label placement Type de document : Article/Communication Auteurs : M. Yamamoto, Auteur ; G. Camara, Auteur ; L.A. Lorena, Auteur Année de publication : 2002 Article en page(s) : pp 77 - 90 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cartographie numérique [Termes IGN] placement automatique des signes conventionnels [Termes IGN] recherche heuristique Résumé : (Auteur) The generation of better label placement configurations in maps is a problem that comes up in automated cartographic production. The objective of a good label placement is to display the geographic position of the features with their corresponding label in a clear and harmonious fashion, following accepted cartographic conventions. In this work, we have approached this problem from a combinatorial optimization point of view, and our research consisted of the evaluation of the tabu search (TS) heuristic applied to cartographic label placement. When compared, in real and random test cases, with techniques such as simulated annealing and genetic algorithm (GA), TS has proven to be an efficient choice, with the best performance in quality. We concluded that TS is a recommended method to solve cartographic label placement problem of point features, due to its simplicity, practicality, efficiency and good performance along with its ability to generate quality solutions in acceptable computational time. Numéro de notice : A2002-110 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1023/A:1013720231747 En ligne : https://doi.org/10.1023/A:1013720231747 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22025 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
057-02011	RAB	Revue	Centre de documentation	En réserve L003	Disponible