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Relations among map objects in cartographic generalization / Stefan Steiniger in Cartography and Geographic Information Science, vol 34 n° 3 (July 2007)  

Public [article]  inCartography and Geographic Information Science > vol 34 n° 3 (July 2007) . - pp 175 - 197 Titre : Relations among map objects in cartographic generalization Type de document : Article/Communication Auteurs : Stefan Steiniger, Auteur ; Robert Weibel, Auteur Année de publication : 2007 Article en page(s) : pp 175 - 197 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] appariement de données localisées [Termes IGN] carte thématique [Termes IGN] carte topographique [Termes IGN] généralisation cartographique automatisée [Termes IGN] information sémantique [Termes IGN] objet cartographique [Termes IGN] relation topologique [Termes IGN] typologie [Vedettes matières IGN] Généralisation Résumé : (Auteur) Adequate representation of cartographic expert knowledge is essential if maps are to be created in an automated way. Part of this expert knowledge is made up by the structural knowledge embedded in the relations that exist among the objects depicted on a map, as these define the structures and patterns of the corresponding real-world objects that should be maintained and emphasized in the cartographic generalization process. With this article we aim to provide a foundation for the analysis and representation of such relations among objects in thematic and topographic maps, which we term horizontal relations. We start off by defining the terminology underlying map object relations and by discussing how these relations interact with map constraints and cartometric measures. We then present a typology of horizontal relations that may be found in a map with respect to map generalization. The typology is the result of a study of thematic and topographic maps, as well as an analysis of the literature on the use of map object relations. Five different types of horizontal relations are identified: geometric, topological, semantic, statistical and structural. Some of these can be based on standard operations available in commercial GIS or mapping systems, while others are less easily accessible. To demonstrate the use of our typology and show how complex horizontal relations can be formalized, we present an application of the typology to the grouping and generalization of islands. Subsequently, we discuss the various steps involved in the usage of horizontal relations in map generalization, as well as their associated roles. Copyright CaGISociety Numéro de notice : A2007-392 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1559/152304007781697866 En ligne : https://doi.org/10.1559/152304007781697866 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28755 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
032-07031	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Testing the effects of thematic uncertainty on spatial decision-making / S. Hope in Cartography and Geographic Information Science, vol 34 n° 3 (July 2007)  

Public [article]  inCartography and Geographic Information Science > vol 34 n° 3 (July 2007) . - pp 199 - 214 Titre : Testing the effects of thematic uncertainty on spatial decision-making Type de document : Article/Communication Auteurs : S. Hope, Auteur ; Gary J. Hunter, Auteur Année de publication : 2007 Article en page(s) : pp 199 - 214 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] analyse spatiale [Termes IGN] incertitude des données [Termes IGN] modélisation [Termes IGN] outil d'aide à la décision [Termes IGN] système d'information géographique Résumé : (Auteur) The output of any Geographic Information System (GIS) is a representation of the real world and, as such, it will always contain some level of uncertainty. There is now a growing recognition that this uncertainty should be communicated to information consumers if they are to be fully informed regarding the decisions being made on the basis of the underlying data. Research to date has tended to focus on the issues of how uncertainty information can be modeled and visualized, with less consideration being given to the subject of how users might apply such information. Studies in the psychological literature clearly indicate decision-making biases when information is ambiguous, with most people displaying ambiguity aversion. Therefore, the research question we seek to answer in this paper is “Do people exhibit a similar bias towards uncertain spatial information?” This paper examines the effects of introducing thematic uncertainty to spatial information in the context of a decision task. The results indicate that many people, including those who consider themselves to be experienced in working with spatial information, do not have an intuitive understanding of how to handle uncertainty in decision-making. Furthermore, our findings reveal that the inclusion of uncertainty information in a GIS output can lead to irrational decisions being made—instead of promoting robust, more fully informed decision-making as intended. Copyright CaGISociety Numéro de notice : A2007-393 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1559/152304007781697884 En ligne : https://doi.org/10.1559/152304007781697884 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28756 [article]

Exemplaires(1)

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032-07031	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Spatial resolution and algorithm choice as modifiers of downslope flow computed from digital elevation models / K. Clarke in Cartography and Geographic Information Science, vol 34 n° 3 (July 2007)  

Public [article]  inCartography and Geographic Information Science > vol 34 n° 3 (July 2007) . - pp 215 - 230 Titre : Spatial resolution and algorithm choice as modifiers of downslope flow computed from digital elevation models Type de document : Article/Communication Auteurs : K. Clarke, Auteur ; S.J. Lee, Auteur Année de publication : 2007 Article en page(s) : pp 215 - 230 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] Californie (Etats-Unis) [Termes IGN] écoulement des eaux [Termes IGN] limite de résolution géométrique [Termes IGN] Matlab [Termes IGN] modèle numérique de terrain [Termes IGN] pente [Termes IGN] représentation du relief Résumé : (Auteur) This research investigated the dependence of computing downslope flow from digital elevation models (DEMs) on two basic elements of the flow calculation: the spatial resolution of the DEM and the algorithm used to compute the downslope flow, specifically how it defines topographic slope and aspect. Six algorithms for downslope flow and downslope accumulation were implemented in MATLAB using different assumptions about components of the computation from the terrain analysis literature. We analyzed the results of downslope flow statistically, thresholded the values to yield streams, and compared the different results with the actual surface streams in the National Hydrographic Database. We repeated the computations using DEMs of 3-m, 30-m, and 90-m resolutions, covering a test area near Santa Barbara, California. We conclude that downslope flow computations are overestimates, and that they are fraught with critical algorithmic assumptions and scale effects. They should be approached with great caution in GIS-based analyses. Copyright CaGISociety Numéro de notice : A2007-394 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1559/152304007781697875 En ligne : https://doi.org/10.1559/152304007781697875 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28757 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
032-07031	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Interpretation and generalization of 3D landscape from lidar data / S. Filin in Cartography and Geographic Information Science, vol 34 n° 3 (July 2007)  

Public [article]  inCartography and Geographic Information Science > vol 34 n° 3 (July 2007) . - pp 231 - 243 Titre : Interpretation and generalization of 3D landscape from lidar data Type de document : Article/Communication Auteurs : S. Filin, Auteur ; N.A. Akel, Auteur ; K. Kemeike, Auteur ; et al., Auteur Année de publication : 2007 Article en page(s) : pp 231 - 243 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] extraction du réseau routier [Termes IGN] généralisation cartographique automatisée [Termes IGN] interprétation automatique [Termes IGN] lasergrammétrie [Termes IGN] placement automatique des objets [Termes IGN] réseau routier [Termes IGN] semis de points [Termes IGN] visualisation 3D [Vedettes matières IGN] Généralisation Résumé : (Auteur) This paper discusses the interpretation and generalization of three-dimensional landscapes derived from laser scanning data. Airborne laser scanning systems provide an unparalleled detailed description of surfaces on a large scale. This level of detail, however, raises questions regarding the effective visual communication of the data. In this paper, we consider visualization from a cartographic perspective, particularly in terms of the generalization of details and enhancement of important features. Our goal is to visualize topography efficiently, while emphasizing such features as the road network. To achieve this, the communication of 3D landscapes has been implemented as a modular pipeline of individual, configurable processes, focusing on the interpretation of the laser dataset and its generalization. The raw laser point-cloud then becomes an input to a sequence of processes that result in a generalized topography. The interpretation process concerns the extraction of the terrain and the road network from the raw data. The generalization of the interpreted entities then follows. The application of the proposed model shows improved manifestation of the road network within the terrain. Copyright CaGISociety Numéro de notice : A2007-395 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1559/152304007781697857 En ligne : https://doi.org/10.1559/152304007781697857 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28758 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
032-07031	RAB	Revue	Centre de documentation	En réserve L003	Disponible