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Topologically correct subdivision simplification using the bandwidth criterion / Mark De Berg in Cartography and geographic information systems, vol 25 n° 4 (October 1998)  

Public [article]  inCartography and geographic information systems > vol 25 n° 4 (October 1998) . - pp 243 - 257 Titre : Topologically correct subdivision simplification using the bandwidth criterion Type de document : Article/Communication Auteurs : Mark De Berg, Auteur ; M. De Kreveld, Auteur ; S. Schirra, Auteur Année de publication : 1998 Article en page(s) : pp 243 - 257 Note générale : Bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Bases de données localisées [Termes IGN] lissage de courbe Résumé : (Auteur) The line simplification problem is an old and well studied problem in cartography. Although there are several algorithms to compute a simplification there seem to be no algorithms that perform line simplification in the context of other geographical objects. This paper presents a nearly quadratic time algorithm for the following line simplification problem: Given a polygonal line, a set of extra points, and a real E> 0, compute a simplification that guarantees (i) a maximum error E; (ii) that the extra points remain on the same side of the simplified chain as of the original chain; and (iii) that the simplified chain has no self intersections. The algorithm is applied as the main subroutine for subdivision simplification and guarantees that the resulting subdivision is topologically correct. Numéro de notice : A1998-151 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1559/152304098782383007 En ligne : https://doi.org/10.1559/152304098782383007 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26118 [article]

Exemplaires(1)

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032-98041	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Rethinking levels of measurement for cartography / Nicholas Chrisman in Cartography and geographic information systems, vol 25 n° 4 (October 1998)  

Public [article]  inCartography and geographic information systems > vol 25 n° 4 (October 1998) . - pp 231 - 242 Titre : Rethinking levels of measurement for cartography Type de document : Article/Communication Auteurs : Nicholas Chrisman, Auteur Année de publication : 1998 Article en page(s) : pp 231 - 242 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cartographie numérique [Termes IGN] cartographie automatique [Termes IGN] taxinomie Résumé : (Auteur) Stevens' measurement levels (nominal, ordinal, interval and ratio) have become a familiar part of cartography and GIS. These levels have been accepted unquestioned from publications in social sciences dating from the 1940s and 1950s. The Stevens taxonomy has been used to prescribe appropriate symbolism (or analytical treatment) to each scale of measurement. This paper reviews the process by which these levels became a part of cartography, as well as subsequent literature that cartographers have all but ignored over the intervening four decades. The paper concludes that the four levels of measurement are not adequate to cover the circumstances of cartography, and that attribute issues alone do not provide a sufficient guide to symbolism or analytical treatment. A broader framework for measurement must be considered, including the relationships of control that constrain variation in one component to permit measurement of another. An informed use of tools does not depend on numbers alone, but on the whole "measurement framework," the system of objects, relationships and axioms implied by a given system of representation. Numéro de notice : A1998-152 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1559/152304098782383043 En ligne : https://doi.org/10.1559/152304098782383043 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26119 [article]

Exemplaires(1)

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032-98041	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Generating street center - lines from inaccurate vector city maps / F. Thomas in Cartography and geographic information systems, vol 25 n° 4 (October 1998)  

Public [article]  inCartography and geographic information systems > vol 25 n° 4 (October 1998) . - pp 221 - 230 Titre : Generating street center - lines from inaccurate vector city maps Type de document : Article/Communication Auteurs : F. Thomas, Auteur Année de publication : 1998 Article en page(s) : pp 221 - 230 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique [Termes IGN] axe médian [Termes IGN] données vectorielles [Termes IGN] extraction automatique [Termes IGN] extraction du réseau routier [Termes IGN] imprécision géométrique [Termes IGN] morphologie mathématique [Termes IGN] réseau routier Résumé : (Auteur) This paper addresses the problem of automatically generating city street networks from a possibly inaccurate vector description of their blocks. The street network, represented as a graph structure with attributes related to both streets and crossings, is a fundamental data struc-ture for a large number of applications, including urban planning and transport management. The considered inaccuracies derive from the typical errors introduced during hand digitizing; i.e., undershooting, overshooting, stacking, and layer misplacing. Extracting the street net when all these possible errors are present is not an easy task because of the huge amount of particular cases to be considered. The presented algorithm is based on the translation of the vector information directly into a runlength encoded binary image. Then, corrections of the above errors and of the street net extraction can be expressed in terms of well known, simple, morphological operations. In order to lower computational costs, the key idea has been to carry out these operations directly on the encoded image. The result is an algorithm that is faster than expected, easy to implement, and, as a consequence, more generally applicable. Numéro de notice : A1998-153 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1559/152304098782383052 En ligne : https://doi.org/10.1559/152304098782383052 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26120 [article]

Exemplaires(1)

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032-98041	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Multi-scale categorical data bases with automatic generalization transformations based on Map Algebra / Olli Jaakkola in Cartography and geographic information systems, vol 25 n° 4 (October 1998)  

Public [article]  inCartography and geographic information systems > vol 25 n° 4 (October 1998) . - pp 195 - 207 Titre : Multi-scale categorical data bases with automatic generalization transformations based on Map Algebra Type de document : Article/Communication Auteurs : Olli Jaakkola, Auteur Année de publication : 1998 Article en page(s) : pp 195 - 207 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] base de données multi-représentation [Termes IGN] généralisation automatique de données [Termes IGN] généralisation cartographique automatisée [Termes IGN] jeu de données localisées [Termes IGN] langage de modélisation [Termes IGN] Map Algebra [Termes IGN] objet géographique zonal [Vedettes matières IGN] Généralisation Résumé : (Auteur) The problem of generalizing spatial data sets has been studied in the context of categorical data. Map Algebra, a deterministic modeling language, has been chosen as the modeling language for the generalization transformations. The methodology is based on simple basic Map Algebra functions, which are brought together and run as a sequenced batch file. From the basic Map Algebra functions, several individual generalization transformations have been composed ; the three most important are described extensively in the paper. The two major practical projects implemented with the automatic generalization transformations are presented. Finally, the results of the methodological development for generalizing categorical databases are presented and the prospects for extending the methodology are discussed. Numéro de notice : A1998-204 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1559/152304098782383016 En ligne : https://doi.org/10.1559/152304098782383016 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26168 [article]

Exemplaires(1)

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032-98041	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Worlds of information: the geographic metaphor in the visualization of complex information / Helen Couclelis in Cartography and geographic information systems, vol 25 n° 4 (October 1998)  

Public [article]  inCartography and geographic information systems > vol 25 n° 4 (October 1998) . - pp 209 - 220 Titre : Worlds of information: the geographic metaphor in the visualization of complex information Type de document : Article/Communication Auteurs : Helen Couclelis, Auteur Année de publication : 1998 Article en page(s) : pp 209 - 220 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cartographie numérique [Termes IGN] information complexe [Termes IGN] ontologie [Termes IGN] visualisation Résumé : (Auteur) This paper explores the potential of the geographic metaphor in helping generate systematic, flexible, and powerful visualizations of textual information. It is part of a larger project aiming at the development of a general spatialization framework for complex nonspatial information. The focus here is on two fundamental questions: first, what is the cognitive rationale for applying the geographic metaphor to nonspatial information; and second, what may be the significance of basic geographic concepts such as place, way, and region within information spaces represented as geographic landscapes. Following a discussion of information spaces in general, the paper examines the notions of situated and embedded cognition, and some principles for the design of spatializations deriving from these. The next section considers the potential meanings, uses, and presentation modes of the geographic concepts of place, way, and region within a spatialized representation of (textual) information. The final discussion and conclusions point towards an informal research agenda for further work in that area. Numéro de notice : A1998-206 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1559/152304098782383034 En ligne : https://doi.org/10.1559/152304098782383034 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26170 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
032-98041	RAB	Revue	Centre de documentation	En réserve L003	Disponible