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Efficient maintenance of continuous queries for trajectories / H. Ding in Geoinformatica, vol 12 n° 3 (September - November 2008)  

Public [article]  inGeoinformatica > vol 12 n° 3 (September - November 2008) . - pp 255 - 288 Titre : Efficient maintenance of continuous queries for trajectories Type de document : Article/Communication Auteurs : H. Ding, Auteur ; Goce Trajcevski, Auteur ; Peter Scheuermann, Auteur Année de publication : 2008 Article en page(s) : pp 255 - 288 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées [Termes IGN] base de données d'objets mobiles [Termes IGN] base de données localisées [Termes IGN] index spatial [Termes IGN] objet mobile [Termes IGN] Oracle 9I [Termes IGN] prise en compte du contexte [Termes IGN] prototype [Termes IGN] requête spatiale Résumé : (Auteur) We address the problem of optimizing the maintenance of continuous queries in Moving Objects Databases, when a set of pending continuous queries need to be reevaluated as a result of bulk updates to the trajectories of moving objects. Such bulk updates may happen when traffic abnormalities, e.g., accidents or road works, affect a subset of trajectories in the corresponding regions, throughout the duration of these abnormalities. The updates to the trajectories may in turn affect the correctness of the answer sets for the pending continuous queries in much larger geographic areas. We present a comprehensive set of techniques, both static and dynamic, for improving the performance of reevaluating the continuous queries in response to the bulk updates. The static techniques correspond to specifying the values for the various semantic dimensions of trigger execution. The dynamic techniques include an in-memory shared reevaluation algorithm, extending query indexing to queries described by trajectories and query reevaluation ordering based on space-filling curves. We have completely implemented our system prototype on top of an existing Object-Relational Database Management System, Oracle 9i, and conducted extensive experimental evaluations using realistic data sets to demonstrate the validity of our approach. Copyright Springer Numéro de notice : A2008-281 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1007/s10707-007-0029-9 En ligne : https://doi.org/10.1007/s10707-007-0029-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29274 [article]

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Generalization-oriented road line classification by means of an artificial neural network / J.L. Garcia Balboa in Geoinformatica, vol 12 n° 3 (September - November 2008)  

Public [article]  inGeoinformatica > vol 12 n° 3 (September - November 2008) . - pp 289 - 312 Titre : Generalization-oriented road line classification by means of an artificial neural network Type de document : Article/Communication Auteurs : J.L. Garcia Balboa, Auteur ; Francisco Javier Ariza-López, Auteur Année de publication : 2008 Article en page(s) : pp 289 - 312 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] acquisition de connaissances [Termes IGN] analyse en composantes principales [Termes IGN] apprentissage dirigé [Termes IGN] axe médian [Termes IGN] classification par réseau neuronal [Termes IGN] généralisation cartographique automatisée [Termes IGN] matrice d'erreur [Termes IGN] objet géographique linéaire [Termes IGN] route [Termes IGN] segmentation [Vedettes matières IGN] Généralisation Résumé : (Auteur) In line generalization, a first goal to achieve is the classification of features previous to the selection of processes and parameters. A feed forward backpropagation artificial neural network (ANN) is designed for classifying a set of road lines through a supervised learning process, attempting to emulate a classification performed by a human expert for cartographic generalization purposes. The main steps of the process are presented in this paper: (a) experimental data selection; (b) segmentation of lines into homogeneous sections, (c) sections enrichment through a set of quantitative measures derived from a principal component analysis, and qualitative information derived from road network and road type; (d) expert classification of the sections; and finally (e) the ANN design, training and validation. The quality of results is analyzed by means of error matrices after a cross-validation process giving a goodness, or percentage of agreement, over 83%. Copyright Springer Numéro de notice : A2008-282 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1007/s10707-007-0026-z En ligne : https://doi.org/10.1007/s10707-007-0026-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29275 [article]

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Efficient implementation techniques for topological predicates on complex spatial objects / R. Praing in Geoinformatica, vol 12 n° 3 (September - November 2008)  

Public [article]  inGeoinformatica > vol 12 n° 3 (September - November 2008) . - pp 313 - 356 Titre : Efficient implementation techniques for topological predicates on complex spatial objects Type de document : Article/Communication Auteurs : R. Praing, Auteur ; Monique Schneider, Auteur Année de publication : 2008 Article en page(s) : pp 313 - 356 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées [Termes IGN] arbre de décision [Termes IGN] données vectorielles [Termes IGN] implémentation (informatique) [Termes IGN] matrice [Termes IGN] méthode robuste [Termes IGN] objet géographique complexe [Termes IGN] optimisation (mathématiques) [Termes IGN] prédicat [Termes IGN] relation topologique Résumé : (Auteur) Topological relationships like overlap, inside, meet, and disjoint uniquely characterize the relative position between objects in space. For a long time, they have been a focus of interdisciplinary research as in artificial intelligence, cognitive science, linguistics, robotics, and spatial reasoning. Especially as predicates, they support the design of suitable query languages for spatial data retrieval and analysis in spatial database systems and geographical information systems. While, to a large extent, conceptual aspects of topological predicates (like their definition and reasoning with them) as well as strategies for avoiding unnecessary or repetitive predicate executions (like predicate migration and spatial index structures) have been emphasized, the development of robust and efficient implementation techniques for them has been largely neglected. Especially the recent design of topological predicates for all combinations of complex spatial data types has resulted in a large increase of their numbers and stressed the importance of their efficient implementation. The goal of this article is to develop correct and efficient implementation techniques of topological predicates for all combinations of complex spatial data types including two-dimensional point, line, and region objects, as they have been specified by different authors and in different commercial and public domain software packages. Our solution consists of two phases. In the exploration phase, for a given scene of two spatial objects, all topological events like intersection and meeting situations are summarized in two precisely defined topological feature vectors (one for each argument object of a topological predicate) whose specifications are characteristic and unique for each combination of spatial data types. These vectors serve as input for the evaluation phase which analyzes the topological events and determines the Boolean result of a topological predicate (predicate verification) or the kind of topological predicate (predicate determination) by a formally defined method called nine-intersection matrix characterization. Besides this general evaluation method, the article presents an optimized method for predicate verification, called matrix thinning, and an optimized method for predicate determination, called minimum cost decision tree. The methods presented in this article are applicable to all known complete collections of mutually exclusive topological predicates that are formally based on the well known nine-intersection model. Copyright Springer Numéro de notice : A2008-283 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1007/s10707-007-0035-y En ligne : https://doi.org/10.1007/s10707-007-0035-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29276 [article]

Exemplaires(1)

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Variable-resolution compression of vector data / B. Yang in Geoinformatica, vol 12 n° 3 (September - November 2008)  

Public [article]  inGeoinformatica > vol 12 n° 3 (September - November 2008) . - pp 357 - 376 Titre : Variable-resolution compression of vector data Type de document : Article/Communication Auteurs : B. Yang, Auteur ; Ross S. Purves, Auteur ; Robert Weibel, Auteur Année de publication : 2008 Article en page(s) : pp 357 - 376 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique [Termes IGN] arc [Termes IGN] compression de données [Termes IGN] données vectorielles [Termes IGN] élimination de points [Termes IGN] noeud [Termes IGN] objet géographique [Termes IGN] résolution multiple Résumé : (Auteur) The compression of spatial data is a promising solution to reduce the space of data storage and to decrease the transmission time of spatial data over the Internet. This paper proposes a new method for variable-resolution compression of vector data. Three key steps are encompassed in the proposed method, namely, the simplification of vector data via the elimination of vertices, the compression of removed vertices, and the decoding of the compressed vector data. The proposed compression method was implemented and applied to compress vector data to investigate its performance in terms of the compression ratio, distortions of geometric shapes. The results show that the proposed method provides a feasible and efficient solution for the compression of vector data, is able to achieve good compression ratios and maintains the main shape characteristics of the spatial objects within the compressed vector data. Copyright Springer Numéro de notice : A2008-284 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1007/s10707-007-0036-x En ligne : https://doi.org/10.1007/s10707-007-0036-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29277 [article]

Exemplaires(1)

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057-08031	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Automatically and accurately conflating raster maps with orthoimagery / C.C. Chen in Geoinformatica, vol 12 n° 3 (September - November 2008)  

Public [article]  inGeoinformatica > vol 12 n° 3 (September - November 2008) . - pp 377 - 410 Titre : Automatically and accurately conflating raster maps with orthoimagery Type de document : Article/Communication Auteurs : C.C. Chen, Auteur ; Craig A. Knoblock, Auteur ; C. Shahabi, Auteur Année de publication : 2008 Article en page(s) : pp 377 - 410 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique [Termes IGN] appariement de points [Termes IGN] carrefour [Termes IGN] carte thématique [Termes IGN] conflation [Termes IGN] données maillées [Termes IGN] données vectorielles [Termes IGN] orthoimage [Termes IGN] réseau routier [Termes IGN] transformation élastique Résumé : (Auteur) Recent growth of geospatial information online has made it possible to access various maps and orthoimagery. Conflating these maps and imagery can create images that combine the visual appeal of imagery with the attribution information from maps. The existing systems require human intervention to conflate maps with imagery. We present a novel approach that utilizes vector datasets as “glue” to automatically conflate street maps with imagery. First, our approach extracts road intersections from imagery and maps as control points. Then, it aligns the two point sets by computing the matched point pattern. Finally, it aligns maps with imagery based on the matched pattern. The experiments show that our approach can conflate various maps with imagery, such that in our experiments on TIGER-maps covering part of St. Louis county, MO, 85.2% of the conflated map roads are within 10.8 m from the actual roads compared to 51.7% for the original and georeferenced TIGER-map roads. Copyright Springer Numéro de notice : A2008-285 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1007/s10707-007-0033-0 En ligne : https://doi.org/10.1007/s10707-007-0033-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29278 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
057-08031	RAB	Revue	Centre de documentation	En réserve L003	Disponible