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Computational method for the point cluster analysis on networks / K. Sugihara in Geoinformatica, vol 15 n° 1 (January 2011)  

Public [article]  inGeoinformatica > vol 15 n° 1 (January 2011) . - pp 167 - 189 Titre : Computational method for the point cluster analysis on networks Type de document : Article/Communication Auteurs : K. Sugihara, Auteur ; Atsuyuki Okabe, Auteur ; T. Satoh, Auteur Année de publication : 2011 Article en page(s) : pp 167 - 189 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] analyse de groupement [Termes IGN] approche hiérarchique [Termes IGN] distance euclidienne [Termes IGN] réseau [Termes IGN] tâche claire Résumé : (Auteur) We present a general framework of hierarchical methods for point cluster analysis on networks, and then consider individual clustering procedures and their time complexities defined by typical variants of distances between clusters. The distances considered here are the closest-pair distance, the farthest-pair distance, the average distance, the median-pair distance and the radius distance. This paper will offer a menu for users to choose hierarchical clustering algorithms on networks from a time complexity point of view. Numéro de notice : A2011-032 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1007/s10707-009-0092-5 Date de publication en ligne : 03/09/2009 En ligne : https://doi.org/10.1007/s10707-009-0092-5 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30813 [article]

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057-2011011	RAB	Revue	Centre de documentation	En réserve L003	Disponible

A kernel density estimation method for networks, its computational method and a GIS-based tool / Atsuyuki Okabe in International journal of geographical information science IJGIS, vol 23 n° 1-2 (january 2009)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 23 n° 1-2 (january 2009) . - pp 7 - 32 Titre : A kernel density estimation method for networks, its computational method and a GIS-based tool Type de document : Article/Communication Auteurs : Atsuyuki Okabe, Auteur ; T. Satoh, Auteur ; K. Sugiharas, Auteur Année de publication : 2009 Article en page(s) : pp 7 - 32 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications SIG [Termes IGN] densité des points [Termes IGN] erreur systématique [Termes IGN] estimation par noyau [Termes IGN] implémentation (informatique) [Termes IGN] module d'extension [Termes IGN] noeud [Termes IGN] réseau routier [Termes IGN] système d'information géographique [Termes IGN] visualisation de données Résumé : (Auteur) We develop a kernel density estimation method for estimating the density of points on a network and implement the method in the GIS environment. This method could be applied to, for instance, finding 'hot spots' of traffic accidents, street crimes or leakages in gas and oil pipe lines. We first show that the application of the ordinary two-dimensional kernel method to density estimation on a network produces biased estimates. Second, we formulate a 'natural' extension of the univariate kernel method to density estimation on a network, and prove that its estimator is biased; in particular, it overestimates the densities around nodes. Third, we formulate an unbiased discontinuous kernel function on a network. Fourth, we formulate an unbiased continuous kernel function on a network. Fifth, we develop computational methods for these kernels and derive their computational complexity; and we also develop a plug-in tool for operating these methods in the GIS environment. Sixth, an application of the proposed methods to the density estimation of traffic accidents on streets is illustrated. Lastly, we summarize the major results and describe some suggestions for the practical use of the proposed methods. Numéro de notice : A2009-125 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810802475491 En ligne : https://doi.org/10.1080/13658810802475491 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29755 [article]

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079-09012	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Generalized network Voronoi diagrams: concepts, computational methods, and applications / Atsuyuki Okabe in International journal of geographical information science IJGIS, vol 22 n° 8-9 (august 2008)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 22 n° 8-9 (august 2008) . - pp 965 - 994 Titre : Generalized network Voronoi diagrams: concepts, computational methods, and applications Type de document : Article/Communication Auteurs : Atsuyuki Okabe, Auteur ; T. Satoh, Auteur ; et al., Auteur Année de publication : 2008 Article en page(s) : pp 965 - 994 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] diagramme de Voronoï [Termes IGN] distance euclidienne [Termes IGN] distance pondérée [Termes IGN] graphe planaire [Termes IGN] milieu urbain [Termes IGN] plus proche voisin, algorithme du [Termes IGN] polygone [Termes IGN] polyligne [Termes IGN] système d'information géographique Résumé : (Auteur) In the real world, there are many phenomena that occur on a network or alongside a network; for example, traffic accidents on highways and retail stores along streets in an urbanized area. In the literature, these phenomena are analysed under the assumption that distance is measured with Euclidean distance on a plane. This paper first examines this assumption and shows an empirical finding that Euclidean distance is significantly different from the shortest path distance in an urbanized area if the distance is less than 500 m. This implies that service areas in urbanized areas cannot be well represented by Voronoi diagrams defined on a plane with Euclidean distance, termed generalized planar Voronoi diagrams. To overcome this limitation, second, this paper formulates six types of Voronoi diagrams defined on a network, termed generalized network Voronoi diagrams, whose generators are given by points, sets of points, lines and polygons embedded in a network, and whose distances are given by inward/outward distances, and additively/multiplicatively weighted shortest path distances. Third, in comparison with the generalized planar Voronoi diagrams, the paper empirically shows that the generalized network Voronoi diagrams can more precisely represent the service areas in urbanized areas than the corresponding planar Voronoi diagrams. Fourth, because the computational methods for constructing the generalized planar Voronoi diagrams in the literature cannot be applied to constructing the generalized network Voronoi diagrams, the paper provides newly developed efficient algorithms using the 'extended' shortest path trees. Last, the paper develops user-friendly tools (that are included in SANET, a toolbox for spatial analysis on a network) for executing these computational methods in a GIS environment. Copyright Taylor & Francis Numéro de notice : A2008-311 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810701587891 En ligne : https://doi.org/10.1080/13658810701587891 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29304 [article]

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Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-08051	RAB	Revue	Centre de documentation	En réserve L003	Disponible
079-08052	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Local statistical spatial analysis [LoSSA]: Inventory and prospect / B. Boots in International journal of geographical information science IJGIS, vol 21 n° 3-4 (march - april 2007)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 21 n° 3-4 (march - april 2007) . - pp 355 - 375 Titre : Local statistical spatial analysis [LoSSA]: Inventory and prospect Type de document : Article/Communication Auteurs : B. Boots, Auteur ; Atsuyuki Okabe, Auteur Année de publication : 2007 Article en page(s) : pp 355 - 375 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] analyse spatiale [Termes IGN] exploration de données géographiques [Termes IGN] géostatistique [Termes IGN] jeu de données localisées Résumé : (Auteur) The past decade has witnessed extensive development of measures that examine characteristics of spatial subsets (local spaces) defined with respect to a complete data set (global space). Such procedures have evolved independently in fields such as geography, GIS, cartography, remote sensing, and landscape ecology. Collectively, we label these procedures as local spatial methods. We focus on those methods that share a common goal of identifying subsets whose characteristics are statistically 'significant' in some way. We propose the concept of local spatial statistical analysis (LoSSA) both as an integrative structure for existing methods and as a framework that facilitates the development of new local and global statistics. By formalizing what is involved when a particular local statistic is used, LoSSA helps to reveal the key features and limitations of the procedure. These include a consideration of the nature of the spatial subsets, their spatial relationship to the complete data set, and the relationship between a given global statistic and the corresponding local statistics computed for the data set. Copyright Taylor & Francis Numéro de notice : A2007-116 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810601034267 En ligne : https://doi.org/10.1080/13658810601034267 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28479 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-07021	RAB	Revue	Centre de documentation	En réserve L003	Disponible
079-07022	RAB	Revue	Centre de documentation	En réserve L003	Disponible