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SKIF-P: a point-based indexing and ranking of web documents for spatial-keyword search / A. Khodaei in Geoinformatica, vol 16 n° 3 (July 2012)  

Public [article]  inGeoinformatica > vol 16 n° 3 (July 2012) . - pp 563 - 596 Titre : SKIF-P: a point-based indexing and ranking of web documents for spatial-keyword search Type de document : Article/Communication Auteurs : A. Khodaei, Auteur ; C. Shahabi, Auteur ; C. Li, Auteur Année de publication : 2012 Article en page(s) : pp 563 - 596 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] base de données localisées [Termes IGN] classement [Termes IGN] indexation documentaire Résumé : (Auteur) There is a significant commercial and research interest in location-based web search engines. Given a number of search keywords and one or more locations (geographical points) that a user is interested in, a location-based web search retrieves and ranks the most textually and spatially relevant web pages. In this type of search, both the spatial and textual information should be indexed. Currently, no efficient index structure exists that can handle both the spatial and textual aspects of data simultaneously and accurately. Existing approaches either index space and text separately or use inefficient hybrid index structures with poor performance and inaccurate results. Moreover, most of these approaches cannot accurately rank web-pages based on a combination of space and text and are not easy to integrate into existing search engines. In this paper, we propose a new index structure called Spatial-Keyword Inverted File for Points to handle point-based indexing of web documents in an integrated/efficient manner. To seamlessly find and rank relevant documents, we develop a new distance measure called spatial tf-idf. We propose four variants of spatial-keyword relevance scores and two algorithms to perform top-k searches. As verified by experiments, our proposed techniques outperform existing index structures in terms of search performance and accuracy. Numéro de notice : A2012-110 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1007/s10707-011-0142-7 Date de publication en ligne : 22/10/2011 En ligne : https://doi.org/10.1007/s10707-011-0142-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31558 [article]

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057-2012031	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Automatic and accurate extraction of road intersections from raster maps / Yao-Yi Chiang in Geoinformatica, vol 13 n° 2 (June 2009)  

Public [article]  inGeoinformatica > vol 13 n° 2 (June 2009) . - pp 121 - 157 Titre : Automatic and accurate extraction of road intersections from raster maps Type de document : Article/Communication Auteurs : Yao-Yi Chiang, Auteur ; C. Shahabi, Auteur ; Craig A. Knoblock, Auteur ; C.C. Chen, Auteur Année de publication : 2009 Article en page(s) : pp 121 - 157 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] carrefour [Termes IGN] carte numérique [Termes IGN] conflation [Termes IGN] connexité (topologie) [Termes IGN] données maillées [Termes IGN] extraction automatique [Termes IGN] extraction du réseau routier [Termes IGN] intégration de données [Termes IGN] réseau routier Résumé : (Auteur) Since maps are widely available for many areas around the globe, they provide a valuable resource to help understand other geospatial sources such as to identify roads or to annotate buildings in imagery. To utilize the maps for understanding other geospatial sources, one of the most valuable types of information we need from the map is the road network, because the roads are common features used across different geospatial data sets. Specifically, the set of road intersections of the map provides key information about the road network, which includes the location of the road junctions, the number of roads that meet at the intersections (i.e., connectivity), and the orientations of these roads. The set of road intersections helps to identify roads on imagery by serving as initial seed templates to locate road pixels. Moreover, a conflation system can use the road intersections as reference features (i.e., control point set) to align the map with other geospatial sources, such as aerial imagery or vector data. In this paper, we present a framework for automatically and accurately extracting road intersections from raster maps. Identifying the road intersections is difficult because raster maps typically contain much information such as roads, symbols, characters, or even contour lines. We combine a variety of image processing and graphics recognition methods to automatically separate roads from the raster map and then extract the road intersections. The extracted information includes a set of road intersection positions, the road connectivity, and road orientations. For the problem of road intersection extraction, our approach achieves over 95% precision (correctness) with over 75% recall (completeness) on average on a set of 70 raster maps from a variety of sources. Copyright Springer Numéro de notice : A2009-073 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1007/s10707-008-0046-3 En ligne : https://doi.org/10.1007/s10707-008-0046-3 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29703 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
057-09021	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Processing optimal sequenced route queries using Voronoi diagrams / M. Sharifzadeh in Geoinformatica, vol 12 n° 4 (December 2008)  

Public [article]  inGeoinformatica > vol 12 n° 4 (December 2008) . - pp 411 - 433 Titre : Processing optimal sequenced route queries using Voronoi diagrams Type de document : Article/Communication Auteurs : M. Sharifzadeh, Auteur ; C. Shahabi, Auteur Année de publication : 2008 Article en page(s) : pp 411 - 433 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées [Termes IGN] calcul d'itinéraire [Termes IGN] diagramme de Voronoï [Termes IGN] espace métrique [Termes IGN] recherche du chemin optimal, algorithme de [Termes IGN] requête spatiale Résumé : (Auteur) The Optimal Sequenced Route (OSR) query strives to find a route of minimum length starting from a given source location and passing through a number of typed locations in a specific sequence imposed on the types of the locations. In this paper, we propose a pre-computation approach to OSR query in both vector and metric spaces. We exploit the geometric properties of the solution space and theoretically prove its relation to additively weighted Voronoi diagrams. Our approach recursively accesses these diagrams to incrementally build the OSR. Introducing the analogous diagrams for the space of road networks, we show that our approach is also efficiently applicable to this metric space. Our experimental results verify that our pre-computation approach outperforms the previous index-based approaches in terms of query response time. Copyright Springer Numéro de notice : A2008-377 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1007/s10707-007-0034-z En ligne : https://doi.org/10.1007/s10707-007-0034-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29370 [article]

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Code-barres	Cote	Support	Localisation	Section	Disponibilité
057-08041	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

Utilizing Voronoi cells of location data streams for accurate computation of aggregate functions in sensor networks / M. Sharifzadeh in Geoinformatica, vol 10 n° 1 (March - May 2006)  

Public [article]  inGeoinformatica > vol 10 n° 1 (March - May 2006) Titre : Utilizing Voronoi cells of location data streams for accurate computation of aggregate functions in sensor networks Type de document : Article/Communication Auteurs : M. Sharifzadeh, Auteur ; C. Shahabi, Auteur Année de publication : 2006 Conférence : ACM GIS 2004, 12th ACM symposium on geographic information systems 12/11/2004 13/11/2004 Arlington Etats-Unis Selected papers Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] agrégation spatiale [Termes IGN] analyse comparative [Termes IGN] diagramme de Voronoï [Termes IGN] données vectorielles [Termes IGN] interpolation spatiale [Termes IGN] requête spatiale [Termes IGN] réseau de capteurs [Termes IGN] Triangulated Irregular Network Résumé : (Auteur) Sensor networks are unattended deeply distributed systems whose database schema can be conceptualized using the relational model. Aggregation queries on the data sampled at each sensor node are the main means to extract the abstract characteristics of the surrounding environment. However, the non-uniform distribution of the sensor nodes in the environment leads to inaccurate results generated by the aggregation queries. In this paper, we introduce "spatial aggregations" that take into consideration the spatial location of each measurement generated by the sensor nodes. We propose the use of spatial interpolation methods derived from the fields of spatial statistics and computational geometry to answer spatial aggregations. In particular, we study Spatial Moving Average (SMA), Voronoi Diagram and Triangulated Irregular Network (TIN). Investigating these methods for answering spatial average queries, we show that the average value on the data samples weighted by the area of the Voronoi cell of the corresponding sensor node, provides the best precision. Consequently, we introduce an algorithm to compute and maintain the accurate Voronoi cell at each sensor node while the location of the others arrive on data stream. We also propose AVC-SW, a novel algorithm to approximate this Voronoi cell over a sliding window that supports dynamism in the sensor network. To demonstrate the performance of in-network implementation of our aggregation operators, we have developed prototypes of two different approaches to distributed spatial aggregate processing. Numéro de notice : A2006-096 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/SOCIETE NUMERIQUE Nature : Article DOI : 10.1007/s10707-005-4884-y En ligne : https://doi.org/10.1007/s10707-005-4884-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27823 [article]

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057-06011	RAB	Revue	Centre de documentation	En réserve L003	Disponible

A road network embedding technique for k-nearest neighbor search in moving object databases / M.R. Kolahdouzan in Geoinformatica, vol 7 n° 3 (September - November 2003)  

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