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A hexagon-based method for polygon generalization using morphological operators / Lu Wang in International journal of geographical information science IJGIS, vol 37 n° 1 (January 2023)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 37 n° 1 (January 2023) Titre : A hexagon-based method for polygon generalization using morphological operators Type de document : Article/Communication Auteurs : Lu Wang, Auteur ; Tinghua Ai, Auteur ; Dirk Burghardt, Auteur ; Yilang Shen, Auteur ; Min Yang, Auteur Année de publication : 2023 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] données maillées [Termes IGN] généralisation cartographique automatisée [Termes IGN] morphologie mathématique [Termes IGN] polygone [Vedettes matières IGN] Généralisation Résumé : (auteur) Numerous methods based on square rasters have been proposed for polygon generalization. However, these methods ignore the inconsistent distance measurement among neighborhoods of squares, which may result in an imbalanced generalization in different directions. As an alternative raster, a hexagon has consistent connectivity and isotropic neighborhoods. This study proposed a hexagon-based method for polygon generalization using morphological operators. First, we defined three generalization operators: aggregation, elimination, and line simplification, based on hexagonal morphological operations. We then used corrective operations with selection, skeleton, and exaggeration to detect, classify, and correct the unreasonably reduced narrow parts of the polygons. To assess the effectiveness of the proposed method, we conducted experiments comparing the hexagonal raster to square raster and vector data. Unlike vector-based methods in which various algorithms simplified either areal objects or exterior boundaries, the hexagon-based method performed both simplifications simultaneously. Compared to the square-based method, the results of the hexagon-based method were more balanced in all neighborhood directions, matched better with the original polygons, and had smoother simplified boundaries. Moreover, it performed with shorter running time than the square-based method, where the minimal time difference was less than 1 min, and the maximal time difference reached more than 50 mins. Numéro de notice : A2023-071 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/13658816.2022.2108036 Date de publication en ligne : 10/08/2022 En ligne : https://doi.org/10.1080/13658816.2022.2108036 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101387 [article]

A typification method for linear building groups based on stroke simplification / Xiao Wang in Geocarto international, vol 36 n° 15 ([15/08/2021])  

Public [article]  inGeocarto international > vol 36 n° 15 [15/08/2021] . - pp 1732 - 1751 Titre : A typification method for linear building groups based on stroke simplification Type de document : Article/Communication Auteurs : Xiao Wang, Auteur ; Dirk Burghardt, Auteur Année de publication : 2021 Article en page(s) : pp 1732 - 1751 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] algorithme de Douglas-Peucker [Termes IGN] alignement [Termes IGN] bâtiment [Termes IGN] généralisation du bâti [Termes IGN] noeud [Termes IGN] objet géographique linéaire [Termes IGN] reconnaissance de formes [Termes IGN] simplification de contour [Termes IGN] triangulation de Delaunay [Vedettes matières IGN] Généralisation Résumé : (auteur) Linear building groups are common patterns and important local structures in large scale maps, which should be carefully generalized. This paper uses the idea of line simplification to typify linear building groups. Firstly, based on the stroke idea, the linear building groups are detected that each building group is related by only one stroke; the collinear and curvilinear patterns are distinguished by calculating the overlap rate between the defined auxiliary polygon and its oriented bounding box. Secondly, the stroke is simplified by removing one node in each iterative step; and the remained nodes are reallocated to the new positions, which serves as the centroids location of the newly typified buildings. Third, the representation (size, shape, elongation, and orientation) of the newly typified buildings are calculated by the geometry information of their corresponding parent buildings. The typification method can be carried out as a progressive process, which iterates over the three steps to derive continuous typification results. The method is tested on two building datasets, and the experimental results demonstrate that the proposed method can achieve good performance by well preserving the original linear patterns in the generalized building groups. Numéro de notice : A2021-569 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10106049.2019.1669725 Date de publication en ligne : 26/09/2019 En ligne : https://doi.org/10.1080/10106049.2019.1669725 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98184 [article]

Privacy-aware visualization of volunteered geographic information (VGI) to analyze spatial activity: A benchmark implementation / Alexander Dunkel in ISPRS International journal of geo-information, vol 9 n° 10 (October 2020)  

Public [article]  inISPRS International journal of geo-information > vol 9 n° 10 (October 2020) . - 20 p. Titre : Privacy-aware visualization of volunteered geographic information (VGI) to analyze spatial activity: A benchmark implementation Type de document : Article/Communication Auteurs : Alexander Dunkel, Auteur ; Marc Löchner, Auteur ; Dirk Burghardt, Auteur Année de publication : 2020 Article en page(s) : 20 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] analyse spatiale [Termes IGN] base de données d'images [Termes IGN] chaîne de traitement [Termes IGN] confidentialité [Termes IGN] données localisées des bénévoles [Termes IGN] protection de la vie privée [Termes IGN] réseau social [Termes IGN] ressources naturelles [Termes IGN] réutilisation des données [Termes IGN] visualisation de données Résumé : (auteur) Through volunteering data, people can help assess information on various aspects of their surrounding environment. Particularly in natural resource management, Volunteered Geographic Information (VGI) is increasingly recognized as a significant resource, for example, supporting visitation pattern analysis to evaluate collective values and improve natural well-being. In recent years, however, user privacy has become an increasingly important consideration. Potential conflicts often emerge from the fact that VGI can be re-used in contexts not originally considered by volunteers. Addressing these privacy conflicts is particularly problematic in natural resource management, where visualizations are often explorative, with multifaceted and sometimes initially unknown sets of analysis outcomes. In this paper, we present an integrated and component-based approach to privacy-aware visualization of VGI, specifically suited for application to natural resource management. As a key component, HyperLogLog (HLL)—a data abstraction format—is used to allow estimation of results, instead of more accurate measurements. While HLL alone cannot preserve privacy, it can be combined with existing approaches to improve privacy while, at the same time, maintaining some flexibility of analysis. Together, these components make it possible to gradually reduce privacy risks for volunteers at various steps of the analytical process. A specific use case demonstration is provided, based on a global, publicly-available dataset that contains 100 million photos shared by 581,099 users under Creative Commons licenses. Both the data processing pipeline and resulting dataset are made available, allowing transparent benchmarking of the privacy–utility tradeoffs. Numéro de notice : A2020-664 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3390/ijgi9100607 Date de publication en ligne : 20/10/2020 En ligne : https://doi.org/10.3390/ijgi9100607 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96141 [article]

Micro diagrams: visualization of categorical point data from location-based social media / Mathias Gröbe in Cartography and Geographic Information Science, Vol 47 n° 4 (July 2020)  

Public [article]  inCartography and Geographic Information Science > Vol 47 n° 4 (July 2020) . - pp 305-320 Titre : Micro diagrams: visualization of categorical point data from location-based social media Type de document : Article/Communication Auteurs : Mathias Gröbe, Auteur ; Dirk Burghardt, Auteur Année de publication : 2020 Article en page(s) : pp 305-320 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] analyse spatiale [Termes IGN] diagramme [Termes IGN] données localisées des bénévoles [Termes IGN] réseau social [Vedettes matières IGN] Géovisualisation Résumé : (Auteur) Location-based social media data from different platforms such as Twitter and Flickr increasingly serve with their point-geocoded content as data sources for a variety of applications. The standard visualization method uses a derivation of point maps, which works well with a limited amount of data, but it suffers from weaknesses related to cluttering and overlapping, especially for sets of categories. We developed a new visualization method for categorical point data, called “Micro Diagrams”, which uses small diagrams to show the percentages of categories and the spatial distribution. The processing steps to derive the micro diagrams start with aggregating the points in a regular grid structure, which is followed by the selection of the diagram type that represents the numerical proportions and the application of a size scaling function to show the amounts of data. Various parameterization options are discussed and the influence of the color selection is analyzed. Finally, a case study combined with a user test presents the strengths and limits of the micro diagram method. Numéro de notice : A2020-189 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/15230406.2020.1733438 Date de publication en ligne : 10/03/2020 En ligne : https://doi.org/10.1080/15230406.2020.1733438 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95154 [article]

Exemplaires(1)

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The International Encyclopedia of Geography: People, The Earth, Environment, and Technology, ch. Map Generalization / William A Mackaness (2017)  

Public Titre de série : The International Encyclopedia of Geography: People, The Earth, Environment, and Technology, ch Titre : Map Generalization Type de document : Chapitre/Contribution Auteurs : William A Mackaness, Auteur ; Dirk Burghardt, Auteur ; Cécile Duchêne , Auteur Editeur : New York, Londres, Hoboken (New Jersey), ... : John Wiley & Sons Année de publication : 2017 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] généralisation cartographique automatisée [Termes IGN] géovisualisation [Termes IGN] système d'information géographique [Vedettes matières IGN] Généralisation Résumé : (auteur) Map generalization is concerned with the optimal display of geographic information in map form. It involves the careful selection of data and the use of a range of abstraction techniques that seek to give emphasis to what is important, while still including sufficient contextualizing information. If geographic phenomena are stored at fine levels of detail, the goal of automated map generalization is to derive maps at coarser (smaller) scales. Traditionally, the focus has been on paper maps, but increasingly map generalization services are available via the web, and accessible to users with relatively little cartographic knowledge who wish to integrate data from multiple sources (including their own). These high levels of automation require us to make explicit the relationships and behaviors among geographic phenomena, in order that we can reason about the complex decision‐making process that is cartographic design. Numéro de notice : H2017-029 Affiliation des auteurs : LASTIG COGIT+Ext (2012-2019) Thématique : GEOMATIQUE Nature : Chapître / contribution nature-HAL : ChOuvrScient DOI : 10.1002/9781118786352.wbieg1015 Date de publication en ligne : 06/03/2017 En ligne : https://doi.org/10.1002/9781118786352.wbieg1015 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91924

Automatic delineation of built-up area at urban block level from topographic maps / Sebastian Muhs in Computers, Environment and Urban Systems, vol 58 (July 2016)  

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Automated generalisation within NMAS in 2016 / Jantien E. Stoter (2016)  

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Thematic workshop on building an ontology of generalisation for on-demand mapping / William A Mackaness (2015)    

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Abstracting geographic information in a data rich world, ch. 1. Map generalisation: fundamental to the modelling and understanding of geographic space / William A Mackaness (2014)  

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Abstracting geographic information in a data rich world, ch. 11. Generalisation in practice within national mapping agencies / Cécile Duchêne (2014)  

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Abstracting geographic information in a data rich world, ch. 12. Conclusion: major achievements and research challenges in generalisation / Dirk Burghardt (2014)  

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Abstracting geographic information in a data rich world / Dirk Burghardt (2014)

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Content zooming and information exploration for web and mobile maps. Adaptation of real-time map generalisation to the information seeking strategies of web and mobile users / Pia Bereuter in Revue internationale de géomatique, vol 23 n° 3 - 4 (septembre 2013 - février 2014)  

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Cartography from pole to pole [ICC 2013] / Manfred F. Buchroithner (2013)  

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Proceedings of the 26th International Cartographic Conference, ICC '13 [ICC 2013] / Manfred F. Buchroithner (2013)  

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