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Building displacement based on the topological structure / Yageng Sun in Cartographic journal (the), Vol 53 n° 3 (August 2016)  

Public [article]  inCartographic journal (the) > Vol 53 n° 3 (August 2016) Titre : Building displacement based on the topological structure Type de document : Article/Communication Auteurs : Yageng Sun, Auteur ; Qingsheng Guo, Auteur ; Yuangang Liu, Auteur ; et al., Auteur Année de publication : 2016 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] algorithme snake [Termes IGN] déplacement d'objet géographique [Termes IGN] généralisation automatique de données [Termes IGN] optimisation (mathématiques) [Termes IGN] partitionnement [Termes IGN] pondération [Termes IGN] relation spatiale [Termes IGN] triangulation de Delaunay [Vedettes matières IGN] Généralisation Résumé : (auteur) Map data at smaller scales than their source can result in spatial conflict, whereby map symbols become too close, or overlaid. Server map generalisation operators may be applied to solve this problem, including displacement. In this paper, we show how an optimisation algorithm, the snake algorithm, was used to displace multiple objects in order to resolve spatial conflicts and maintain important spatial relationships between objects during displacement. Two principles based on the snake algorithm are proposed in this paper. First, the truss structure mirroring spatial proximity relationships between buildings and between building and road is formed based on the weighted proximity graph derived from constrained Delaunay triangulations (CDT) in each map partition. In the weighted proximity graph, each connecting line is determined as a snake and as an element unit to assemble the global stiffness matrix in snake algorithm. Second, a buffer method that calculates force between a building and a road (or other linear features) or between pair of buildings is adopted in the snake algorithm. This avoids the imbalance phenomenon caused by different force calculation methods during the displacement. The feasibility of the approach is demonstrated in obtaining real geographic data. Finally, the results are cartographically usable and in particular, the spatial relationships between objects are preserved. Numéro de notice : A2016-680 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1179/1743277414Y.0000000089 En ligne : http://dx.doi.org/10.1179/1743277414Y.0000000089 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81937 [article]

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The Visvalingam algorithm: metrics, measures and heuristics / Mahes Visvalingam in Cartographic journal (the), Vol 53 n° 3 (August 2016)  

Public [article]  inCartographic journal (the) > Vol 53 n° 3 (August 2016) . - pp 242 - 252 Titre : The Visvalingam algorithm: metrics, measures and heuristics Type de document : Article/Communication Auteurs : Mahes Visvalingam, Auteur Année de publication : 2016 Article en page(s) : pp 242 - 252 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] algorithme de généralisation [Termes IGN] algorithme de Visvalingam [Termes IGN] généralisation cartographique automatisée [Termes IGN] littoral [Termes IGN] méthode heuristique [Termes IGN] métrique [Vedettes matières IGN] Généralisation Résumé : (auteur) This paper provides the background necessary for a clear understanding of forthcoming papers relating to the Visvalingam algorithm for line generalization, for example on the testing and usage of its implementations. It distinguishes the algorithm from implementation-specific issues to explain why it is possible to get inconsistent but equally valid output from different implementations. By tracing relevant developments within the now-disbanded Cartographic Information Systems Research Group (CISRG) of the University of Hull, it explains why (a) a partial metric-driven implementation was, and still is, sufficient for many projects but not for others; (b) why the effective area (EA) is a measure derived from a metric; (c) why this measure (EA) may serve as a heuristic indicator for in-line feature segmentation and model-based generalization; (d) how metrics may be combined to change the order of point elimination; and (e) how Tobler's rule-of-thumb is useful for scale-related filtering of EA. The issues discussed in this paper also apply to the use of other metrics. It is hoped that the background and guidance provided in this paper will enable others to participate in further research based on the algorithm. Numéro de notice : A2016-681 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00087041.2016.1151097 En ligne : http://dx.doi.org/10.1080/00087041.2016.1151097 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81938 [article]

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Implications of weighting metrics for line generalization with Visvalingam's algorithm / Mahes Visvalingam in Cartographic journal (the), Vol 53 n° 3 (August 2016)  

Public [article]  inCartographic journal (the) > Vol 53 n° 3 (August 2016) . - pp 253 - 267 Titre : Implications of weighting metrics for line generalization with Visvalingam's algorithm Type de document : Article/Communication Auteurs : Mahes Visvalingam, Auteur ; J.C. Whelan, Auteur Année de publication : 2016 Article en page(s) : pp 253 - 267 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] algorithme de Visvalingam [Termes IGN] littoral [Termes IGN] métrique [Termes IGN] pondération [Termes IGN] retour d'expérience technique [Termes IGN] simplification de contour [Vedettes matières IGN] Généralisation Résumé : (auteur) Visvalingam's algorithm was designed for caricatural line generalization. A distinction must be made between the algorithm and its operational definition, which includes the metric used to drive it. When the algorithm was first introduced, it was demonstrated using the concept of the effective area of triangles. It was noted that alternative metrics could be used and that the metrics could be weighted, for example to take account of shape. Ordnance Survey (Great Britain) and others are using Visvalingam's algorithm for generalizing coastlines and other natural features, with complex parameter-driven functions to weight the original metric. This paper shows how free software and data were used to scrutinize the implications of one of Matthew Bloch's simple and transparent weighting functions. The results look promising, when compared with manually produced mid and small-scale maps; and encourage further research focussed on weighting functions and related topics, such as self-intersection of lines and model-based generalization. The paper discusses why weights were used in some projects. It comments on their range of applicability and reiterates the original guidance provided for the use of weights. It also demonstrates how weights can undermine the algorithm's capacity to draw caricatures with very few points. The paper provides sufficient background and links to the authors’ test data and to open source software for the benefit of others wishing to undertake research in line generalization using Visvalingam's algorithm. Numéro de notice : A2016-682 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00087041.2016.1149906 En ligne : http://dx.doi.org/10.1080/00087041.2016.1149906 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81942 [article]

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The 3d model-map of Cadiz (1779): A unique project of cartography in modern Spain / Gabriel Granado-Castro in Cartographic journal (the), Vol 53 n° 3 (August 2016)  

Public [article]  inCartographic journal (the) > Vol 53 n° 3 (August 2016) . - pp 268 - 281 Titre : The 3d model-map of Cadiz (1779): A unique project of cartography in modern Spain Type de document : Article/Communication Auteurs : Gabriel Granado-Castro, Auteur ; Andrés Martín-Pastor, Auteur Année de publication : 2016 Article en page(s) : pp 268 - 281 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cartographie ancienne [Termes IGN] bâtiment militaire [Termes IGN] Cadix [Termes IGN] carte militaire [Termes IGN] Espagne [Termes IGN] histoire [Termes IGN] ingénieur militaire [Termes IGN] plan-relief Résumé : (auteur) The goal of this article is to analyse several aspects of the construction of a unique project in cartography: the three-dimensional model of the city of Cadiz constructed between 1777 and 1779. Cadiz was the most important fortification in Spain at the time. We focus on new investigations of the two documentary sources relating to the construction of this maquette, or relief map, which hitherto have not been studied in conjunction. This approach facilitates an elucidation of the details of the production of the relief map that benefits from improved knowledge regarding materials, tools, construction techniques and the cost of preparing the model. Additionally, new conclusions are drawn regarding the true utility of maquettes at court and the possible causes of the sudden cancellation of this military project. Numéro de notice : A2016-683 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/00087041.2016.1149263 En ligne : http://dx.doi.org/10.1080/00087041.2016.1149263 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81943 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
030-2016031	RAB	Revue	Centre de documentation	En réserve L003	Disponible