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A global kinetic spatial data structure for a marine simulation / Mir Abolfazl Mostafavi in International journal of geographical information science IJGIS, vol 18 n° 3 (april - may 2004)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 18 n° 3 (april - may 2004) . - pp 211 - 227 Titre : A global kinetic spatial data structure for a marine simulation Type de document : Article/Communication Auteurs : Mir Abolfazl Mostafavi, Auteur Année de publication : 2004 Article en page(s) : pp 211 - 227 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Information géographique [Termes IGN] circulation océanique [Termes IGN] courant marin [Termes IGN] diagramme de Voronoï [Termes IGN] données localisées dynamiques [Termes IGN] données maillées [Termes IGN] littoral [Termes IGN] modèle conceptuel de données localisées [Termes IGN] relation topologique [Termes IGN] simulation [Termes IGN] simulation dynamique [Termes IGN] structure de données localisées [Termes IGN] triangulation de Delaunay Résumé : (Auteur) This paper proposes a new Free-Lagrange method based on the kinetic Voronoi diagram for fluid simulation. The objective here is to combine the advantages of an adoptive mesh structure with the advantages of kinetic mesh maintenance, and demonstrate their value for dynamic simulation. Despite the theoretical advantages of the Free-Lagrange method, its use has been handicapped with the reconstruction of topology after each time step that considerably reduces the efficiency of the method. In addition, the use of fixed time steps causes problems such as overshoots and undetected collisions. In order to demonstrate the ability of the proposed model to solve these problems, the method is applied to a dam-breaking problem and global tides. With the results obtained from these numerical experiments, the validity of the global kinetic data structure is approved. In particular, the method is found to be more efficient than existing methods. In addition, qualitative comparison of physical results with analytical solutions demonstrates the similarity of the results and confirms the physical validity of the proposed method. Further investigations with real-world data and the complete equation of motion are suggested to compare it with other numerical methods. Numéro de notice : A2004-158 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810310001620942 En ligne : https://doi.org/10.1080/13658810310001620942 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26685 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-04031	RAB	Revue	Centre de documentation	En réserve L003	Disponible
079-04032	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Comparing geospatial entity classes: an asymmetric and context-dependent similarity measure / M. Andrea Rodríguez in International journal of geographical information science IJGIS, vol 18 n° 3 (april - may 2004)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 18 n° 3 (april - may 2004) . - pp 229 - 256 Titre : Comparing geospatial entity classes: an asymmetric and context-dependent similarity measure Type de document : Article/Communication Auteurs : M. Andrea Rodríguez, Auteur ; Max J. Egenhofer, Auteur Année de publication : 2004 Article en page(s) : pp 229 - 256 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées [Termes IGN] analyse comparative [Termes IGN] appariement géométrique [Termes IGN] classe d'objets [Termes IGN] distance [Termes IGN] données hétérogènes [Termes IGN] généralisation automatique de données [Termes IGN] identification automatique [Termes IGN] prise en compte du contexte [Termes IGN] recherche d'information géographique [Termes IGN] similitude sémantique [Termes IGN] système d'information géographique Résumé : (Auteur) Semantic similarity plays an important role in geographic information systems as it supports the identification of objects that are conceptually close, but not identical. Similarity assessments are particularly important for retrieval of geospatial data in such settings as digital libraries, heterogeneous databases, and the World Wide Web. Although some computational models for semantic similarity assessment exist, these models are typically limited by their inability to handle such important cognitive properties of similarity judgements as their inherent asymmetry and their dependence on context. This paper defines the Matching-Distance Similarity Measure (MDSM) for determining semantic similarity among spatial entity classes, taking into account the distinguishing features of these classes (parts, functions, and attributes) and their semantic interrelations (is-a and part-whole relations). A matching process is combined with a semantic-distance calculation to obtain asymmetric values of similarity that depend on the degree of generalization of entity classes. MDSM's matching process is also driven by contextual considerations, where the context determines the relative importance of distinguishing features. Based on a human-subject experiment, MDSM results correlate well with people's judgements of similarity. When contextual information is used for determining the importance of distinguishing features, this correlation increases; however, the major component of the correlation between MDSM results and people's judgements is due to a detailed definition of entity classes. Numéro de notice : A2004-159 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1080/13658810310001629592 En ligne : https://doi.org/10.1080/13658810310001629592 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26686 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-04031	RAB	Revue	Centre de documentation	En réserve L003	Disponible
079-04032	RAB	Revue	Centre de documentation	En réserve L003	Disponible

The scale matcher: a procedure for assessing scale compatibility of spatial data and models / L.R. Lilburne in International journal of geographical information science IJGIS, vol 18 n° 3 (april - may 2004)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 18 n° 3 (april - may 2004) . - pp 257 - 279 Titre : The scale matcher: a procedure for assessing scale compatibility of spatial data and models Type de document : Article/Communication Auteurs : L.R. Lilburne, Auteur ; T.H. Webb, Auteur ; G.L. Benwell, Auteur Année de publication : 2004 Article en page(s) : pp 257 - 279 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées [Termes IGN] appariement [Termes IGN] échelle cartographique [Termes IGN] mise à l'échelle [Termes IGN] modélisation spatiale [Termes IGN] outil d'aide à la décision [Termes IGN] variation d'échelle Résumé : (Auteur) It is becoming easier to combine environmental data and models to provide information for problem-solving by environmental policy analysts, decision-makers, and land managers. However, the scale dependencies of each of these (data, model, and problem) can mean that the resulting information is misleading or even invalid. This paper describes the development of a systematic framework (dubbed the 'Scale Matcher') for identifying and matching the scale requirements of a problem with the scale limitations of spatial data and models. The Scale Matcher framework partitions the complex array of scale issues into more manageable components that can be individually quantified. First, the scale characteristics of data, model, and problem are separated into their scale components of extent, accuracy, and precision, and each is associated with suitable metrics. Second, a comprehensive set of pairwise matches between these components is defined. Third, a procedure is devised to lead the user through a process of systematically comparing or matching each scale component. In some cases, the matches are simple comparisons of the relevant metrics. Others require the combination of data variability and model sensitivity to be investigated by randomly simulating data and model imprecision and inaccuracy. Finally, a conclusion is drawn as to the scale compatibility of the Data Model-Problem trio based on the overall procedure result. Listing the individual match results as a set of scale assumptions helps to draw attention to them, making users more aware of the limitations of spatial modelling. Application of the Scale Matcher is briefly illustrated with a case study, in which the scale suitability of two sources of soil map data for identifying areas of vulnerability to groundwater pollution was tested. The Scale Matcher showed that one source of soil map data had unacceptable scale characteristics, and the other was marginal for addressing the problem of nitrate leaching vulnerability. The scale-matching framework successfully partitioned the scale issue into a series of more manageable comparisons and gave the user more confidence in the scale validity of the model output. Numéro de notice : A2004-160 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1080/13658810310001629628 En ligne : https://doi.org/10.1080/13658810310001629628 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26687 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-04031	RAB	Revue	Centre de documentation	En réserve L003	Disponible
079-04032	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Visualization of the spatial patterns of inter-urban income disparities using coordinate transformations / R. Gluhih in International journal of geographical information science IJGIS, vol 18 n° 3 (april - may 2004)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 18 n° 3 (april - may 2004) . - pp 281 - 297 Titre : Visualization of the spatial patterns of inter-urban income disparities using coordinate transformations Type de document : Article/Communication Auteurs : R. Gluhih, Auteur ; B.A. Portnov, Auteur Année de publication : 2004 Article en page(s) : pp 281 - 297 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cartographie thématique [Termes IGN] carte thématique [Termes IGN] disparité [Termes IGN] Israël [Termes IGN] milieu urbain [Termes IGN] revenu [Termes IGN] transformation de coordonnées [Termes IGN] urbanisation [Termes IGN] ville [Termes IGN] visualisation Résumé : (Auteur) Inter-urban income disparities reflect differences between individual urban localities in the average incomes of their residents. The present paper discusses different ways of visualizing such disparities on thematic maps. The approach we propose is based on the transformation of distances between individual localities and a reference city (e.g. a major population centre of a country) in proportion to the actual differences in the income levels. The general principle of such a transformation is to bring closer to the reference city places with higher incomes, while moving away localities with low income levels. Three alternative approaches to the implementation of this transformation technique are discussed. According to the 'actual distance' method, the spatial 'shift' of a locality on the map is set proportional to both the relative difference in incomes and the aerial distance between a locality and the reference city. In the 'proportional increment' transformation, the distance between a locality and the reference city is adjusted by a parameter whose values are proportional to income disparities between the two. Lastly, according to the 'concentric circle' transformation, localities with identical levels of incomes are positioned at a certain distance from the reference city, forming concentric circles around it. Both advantages and disadvantages of these transformation techniques are discussed, and the 'proportional increment' method is chosen as the best-performing visualization technique. The performance of this technique is demonstrated using income data for urban localities in Israel in 1991 and 1999. As analysis indicates, the proposed method helps to illustrate both the existing patterns of inter-urban income disparities and their dynamics over time. Numéro de notice : A2004-161 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810310001620951 En ligne : https://doi.org/10.1080/13658810310001620951 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26688 [article]

Exemplaires(2)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-04031	RAB	Revue	Centre de documentation	En réserve L003	Disponible
079-04032	RAB	Revue	Centre de documentation	En réserve L003	Disponible