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Weight-setting and quality assessment in simultaneous graphic generalization / Lars Harrie in Cartographic journal (the), vol 40 n° 3 (December 2003)
[article]
Titre : Weight-setting and quality assessment in simultaneous graphic generalization Type de document : Article/Communication Auteurs : Lars Harrie, Auteur Année de publication : 2003 Article en page(s) : pp 221 - 233 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] contrainte d'intégrité
[Termes IGN] estimation des charges
[Termes IGN] généralisation cartographique automatisée
[Termes IGN] qualité des données
[Vedettes matières IGN] GénéralisationRésumé : (Auteur) Cartographic generalization aims at simplifying the representation of data to suit the scale and purpose of the map. This paper deals with a method that implements the whole graphic generalization process (roughly defined as the operators simplification, smoothing, exaggeration and displacement) called simultaneous graphic generalization. This method is based on constraints, i.e. requirements that should befulfilled in the generalization process. The constraints strive to make the map readable while preserving the characteristics of the data, which implies that all constraints cannot be completely satisfied. This study was concentrated on finding the optimal compromise between the constraints in simultaneous graphic generalization by setting weights for the constraints. Four strategies for determining the weights are described and their advantages and disadvantages are discussed. The discussion is based on the following assumptions: the constraints are independent, and the weights are only dependent on constraint type and object type. A comparison of the strategies reveals that the strategy constraint violation is the most promising. One advantage with this strategy is that it is related to the quality requirements of the map, and another advantage is that it provides a numerical measure for quality assessment. The paper concludes with a case study of the constraint violation strategy, in which visualization of the numerical quality measure is used. The case study shows that the constraint violation strategy gives a sound compromise between the constraints. Numéro de notice : A2003-373 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1179/000870403225012925 En ligne : https://doi.org/10.1179/000870403225012925 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26453
in Cartographic journal (the) > vol 40 n° 3 (December 2003) . - pp 221 - 233[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 030-03031 RAB Revue Centre de documentation En réserve L003 Disponible Simultaneous graphic generalization of vector data sets / Lars Harrie in Geoinformatica, vol 6 n° 3 (September - November 2002)
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Titre : Simultaneous graphic generalization of vector data sets Type de document : Article/Communication Auteurs : Lars Harrie, Auteur ; Tapani Sarjakoski, Auteur Année de publication : 2002 Article en page(s) : pp 233 - 261 Langues : Anglais (eng) Descripteur : [Termes IGN] C++
[Termes IGN] données vectorielles
[Termes IGN] généralisation automatique de données
[Termes IGN] généralisation cartographique automatisée
[Termes IGN] méthode des moindres carrés
[Termes IGN] méthode du gradient conjugué
[Termes IGN] objet géographique ponctuel
[Termes IGN] optimisation (mathématiques)
[Termes IGN] triangulation de Delaunay
[Vedettes matières IGN] GénéralisationRésumé : (Auteur) Manual cartographic generalization is a simultaneous process. However, most automatic approaches so far have been sequential ; generalization operators are applied one at a time in a certain order. This has been the case both for model generalization (generalization of the conceptual model) and graphic generalization. Our research seeks to demonstrate that the graphic part of cartographic generalization can be formulated as an optimization problem and accordingly be solved in a single step. This paper deals with several issues regarding this optimization approach. Firstly, a set of appropriate analytical constraints for the generalization process is given, as well as rules for when to apply these constraints. In our approach, we are limited to formulating these constraints on point locations. Secondly, leastsquares adjustment is proposed to find the optimal solution according to the constraints. Finally, the conjugate gradients method is recommended for solving the normal equations. A prototype system for simultaneous graphic generalization has been implemented in C++, which communicates with a commercial map production system. Results from three tests of the prototype system are included in the paper. Numéro de notice : A2002-204 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1023/A:1019765902987 En ligne : https://doi.org/10.1023/A:1019765902987 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22119
in Geoinformatica > vol 6 n° 3 (September - November 2002) . - pp 233 - 261[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 057-02031 RAB Revue Centre de documentation En réserve L003 Disponible An optimisation approach to cartographic generalisation / Lars Harrie (2001)
Titre : An optimisation approach to cartographic generalisation : doctoral thesis Type de document : Thèse/HDR Auteurs : Lars Harrie, Auteur Editeur : Lund [Suède] : Lund University Année de publication : 2001 Importance : 196 p. Format : 16 x 23 cm ISBN/ISSN/EAN : 978-91-628-4652-7 Note générale : bibliographie
Doctoral thesisLangues : Français (fre) Descripteur : [Termes IGN] base de données orientée objet
[Termes IGN] contrainte de cohérence
[Termes IGN] contrainte géométrique
[Termes IGN] généralisation cartographique
[Termes IGN] généralisation cartographique automatisée
[Termes IGN] méthode des moindres carrés
[Termes IGN] mise à jour de base de données
[Termes IGN] optimisation (mathématiques)
[Termes IGN] programmation par contraintes
[Termes IGN] représentation multiple
[Vedettes matières IGN] GénéralisationIndex. décimale : 37.70 Généralisation Résumé : (auteur) Cartographic generalisation is the process of simplifying a representation to suit the scale and purpose of a map. As such, generalisation has always been a central part in map production. This thesis is a contribution to the ongoing work on automating cartographic generalisation. Two topics are treated: optimisation methods in graphic generalisation, and propagation of updates between cartographic data sets of different scales. To enable an optimisation approach to graphic generalisation several topics are studied. Firstly, requirements are stated for defining a good map. These requirements can act as constraints and control the graphic generalisation process. In this thesis, ten analytical constraints for graphic generalisation are proposed, some for single objects and some for groups of objects. Rules are also established regarding when these constraints should be set up. Secondly, the least-squares method is studied as an approach to finding the optimal solution according to the constraints. Related to this, weighting strategies for the constraints are also discussed. Thirdly, computationally efficient methods are tested, which are especially important for establishing spatial relationships between objects and solving the large normal equation systems. Finally, the optimisation approach has been evaluated visually and quantitatively in mid-scale applications. Mapping organisations have to maintain cartographic data sets of different scales (resolutions). Ideally, mapping organisations should only be concerned with updating the most detailed data set and the updates should automatically be propagated to all other data sets. In this study, a prototype system was created for automatic propagation of updates. This system is integrated in an object-oriented map production software, in which the data sets are stored in a multiple representation database. The rules implemented in the prototype system were gathered from data set specifications and by studying printed map series. The propagation of updates performed by the prototype system was compared with manual propagation performed by a cartographer. Note de contenu : 1- Introduction
2- Cartographic generalisation concepts
3- Spatial concepts
4- Review of generalisation research
5- Summary of the papersNuméro de notice : 17192 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Thèse étrangère Note de thèse : Doctoral thesis : Surveying : Lund University : 2001 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81159 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 17192-01 37.70 Livre Centre de documentation Géomatique Disponible A prototype system for propagating updates between cartographic data sets / Lars Harrie in Cartographic journal (the), vol 36 n° 2 (December 1999)
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Titre : A prototype system for propagating updates between cartographic data sets Type de document : Article/Communication Auteurs : Lars Harrie, Auteur ; A.-K. Hellstrom, Auteur Année de publication : 1999 Article en page(s) : pp 133 - 140 Note générale : Bibliographie 1 page Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées
[Termes IGN] base de données localisées
[Termes IGN] données cartographiques
[Termes IGN] jeu de données localisées
[Termes IGN] mise à jour de base de données
[Termes IGN] représentation multipleRésumé : Présentation d'un prototype de propagation des mises à jour entre des lots de données cartographiques à différentes échelles. Ce prototype est basé sur un cadre conceptuel en 4 étapes : examen, propagation, généralisation des mises à jour et résolution des conflits spatiaux. Une carte produite avec ce prototype est comparée avec une carte produite manuellement par des cartographes. Numéro de notice : A1999-073 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1179/caj.1999.36.2.133 En ligne : https://doi.org/10.1179/caj.1999.36.2.133 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26278
in Cartographic journal (the) > vol 36 n° 2 (December 1999) . - pp 133 - 140[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 030-99021 RAB Revue Centre de documentation En réserve L003 Disponible The constraint method for solving spatial conflicts in cartographic generalization / Lars Harrie in Cartography and Geographic Information Science, vol 26 n° 1 (January 1999)
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Titre : The constraint method for solving spatial conflicts in cartographic generalization Type de document : Article/Communication Auteurs : Lars Harrie, Auteur Année de publication : 1999 Article en page(s) : pp 55 - 69 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] conflit d'espace
[Termes IGN] déplacement d'objet géographique
[Termes IGN] généralisation cartographique automatisée
[Termes IGN] implémentation (informatique)
[Vedettes matières IGN] GénéralisationRésumé : (Auteur) New methods are needed to automate cartographic generalization. This article presents a method for automating the displacement of vector data, called the constraint method. The framework of the method consists of five displacement behavior types. Each cartographic object type belongs to one of these displacement behavior types, which determines the properties of the object type in the displacement process. The displacement behavior types are specified by a set of rules called constraints. The constraint method works as follows. First, it is determined which objects should participate in the displacement process. Then, for each object a set of constraints is set up, depending on its displacement behaviour type. All the constraints build up an overdetermined equation system. This equation system gives how much each object must be moved and/or distorted to solve the spatial conflict. The paper concludes with two applications. Numéro de notice : A1999-171 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1559/152304099782424884 En ligne : https://doi.org/10.1559/152304099782424884 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26369
in Cartography and Geographic Information Science > vol 26 n° 1 (January 1999) . - pp 55 - 69[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 032-99011 RAB Revue Centre de documentation En réserve L003 Disponible Generalisation methods for propagating updates between cartographic data sets / Lars Harrie (1998)Permalink