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Auteur L. Yang |
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Generation of navigation graphs for indoor space / L. Yang in International journal of geographical information science IJGIS, vol 29 n° 10 (October 2015)
[article]
Titre : Generation of navigation graphs for indoor space Type de document : Article/Communication Auteurs : L. Yang, Auteur ; Michael F. Worboys, Auteur Année de publication : 2015 Article en page(s) : pp 1737 - 1756 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Navigation et positionnement
[Termes IGN] graphe
[Termes IGN] graphe topologique
[Termes IGN] modèle géométrique du bâti
[Termes IGN] positionnement en intérieurRésumé : (auteur) This article proposes a comprehensive approach to computing a navigation graph for an indoor space. It focuses on a single floor, but the work is easily extensible to multi-level spaces. The approach proceeds by using a formal model, based on the combinatorial map but enhanced with geometric and semantic information. The process is almost fully automatic, taking as input the building plans providing the geometric structure of the floors and semantics of the building, such as functions of interior spaces, portals, etc. One of the novel aspects in this work was the use of combinatorial maps and their duals to provide a compact formal description of the topology and connectivity of the indoor structure represented by a connected, embedded graph. While making use of existing libraries for the more routine computational geometry involved, the research develops several new algorithms, including one for computing the local kernel of a region. The process is evaluated by means of a case study using part of a university building. Numéro de notice : A2015-610 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/13658816.2015.1041141 En ligne : https://doi.org/10.1080/13658816.2015.1041141 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=78039
in International journal of geographical information science IJGIS > vol 29 n° 10 (October 2015) . - pp 1737 - 1756[article]Detecting geometric conflicts for generalisation of polygonal maps / Wenxiu Gao in Cartographic journal (the), vol 49 n° 1 (February 2012)
[article]
Titre : Detecting geometric conflicts for generalisation of polygonal maps Type de document : Article/Communication Auteurs : Wenxiu Gao, Auteur ; J. Gong, Auteur ; L. Yang, Auteur ; et al., Auteur Année de publication : 2012 Article en page(s) : pp 21 - 29 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] conflit d'espace
[Termes IGN] généralisation cartographique automatisée
[Termes IGN] polygone
[Termes IGN] zone tampon
[Vedettes matières IGN] GénéralisationRésumé : (Auteur) Polygon generalisation is an essential process to produce multi-scale polygonal maps which are able to visualize categorical data at various levels of detail and with multiple themes. Detecting geometric conflicts, existing within an individual polygon and between polygons, is a primary step for polygon generalisation. This paper designs an inward-outward-buffering approach to detect narrow conflicts within an individual polygon. The approach not only detects the existence of narrow sections but also indicates their exact locations inside polygons. Another approach is presented to detect proximity conflicts in between polygons with two main steps. The first step associates buffering with an optimized proximity index to explore possible polygon clusters and spatial contexts around a problematic polygon. Based on the detected polygon clusters, the conflict regions are identified by combining outward-inward-buffering with topological operators. The tests with a real landuse dataset and two maps from other papers demonstrate that the presented approaches not only detect geometric conflict effectively, but also provide useful information for the selection of subsequent generalisation operators. Numéro de notice : A2012-169 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1179/1743277411Y.0000000016 Date de publication en ligne : 22/11/2013 En ligne : https://doi.org/10.1179/1743277411Y.0000000016 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31616
in Cartographic journal (the) > vol 49 n° 1 (February 2012) . - pp 21 - 29[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 030-2012011 RAB Revue Centre de documentation En réserve L003 Disponible Urban land-cover change detection through sub-pixel imperviousness mapping using remotely sensed data / L. Yang in Photogrammetric Engineering & Remote Sensing, PERS, vol 69 n° 9 (September 2003)
[article]
Titre : Urban land-cover change detection through sub-pixel imperviousness mapping using remotely sensed data Type de document : Article/Communication Auteurs : L. Yang, Auteur ; George Xian, Auteur ; J.M. Klaver, Auteur ; B. Deal, Auteur Année de publication : 2003 Article en page(s) : pp 1003 - 1010 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] analyse diachronique
[Termes IGN] croissance urbaine
[Termes IGN] détection de changement
[Termes IGN] Géorgie (Etats-Unis)
[Termes IGN] image Landsat-ETM+
[Termes IGN] image Landsat-TM
[Termes IGN] occupation du sol
[Termes IGN] pixel
[Termes IGN] utilisation du solRésumé : (Auteur) We developed a Sub-pixel Imperviousness Change Detection (SICD) approach to detect urban land-cover changes using Landsat and high-resolution imagery. The sub-pixel percent imperviousness was mapped for two dates (09 March 1993 and 11 March 2001) over western Georgia using a regression tree algorithm. The accuracy of the predicted imperviousness was reasonable based on a comparison using independent reference data. The average absolute error between predicted and reference data was 16.4 percent for 1993 and 15.3 percent for 2001. The correlation coefficient (r) was 0.73 for 1993 and 0.78 for 2001, respectively. Areas with a significant increase (greater than 20 percent) in impervious surface from 1993 to 2001 were mostly related to known land-cover/land-use changes that occurred in this area, suggesting that the spatial change of an impervious surface is a useful indicator for identifying spatial extent, intensity, and, potentially, type of urban land-cover/land-use changes. Compared to other pixel-based change detection methods (band differencing, rationing, change vector, post-classification), information on changes in sub-pixel percent imperviousness allow users to quantify and interpret urban land-cover/land-use changes based on their own definition. Such information is considered complementary to products generated using other change detection methods. In addition, the procedure for mapping imperviousness is objective and repeatable, hence, can be used for monitoring urban land-cover/land-use change over a large geographic area. Potential applications and limitations of the products developed through this study in urban environmental studies are also discussed. Numéro de notice : A2003-230 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.69.9.1003 En ligne : https://doi.org/10.14358/PERS.69.9.1003 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22525
in Photogrammetric Engineering & Remote Sensing, PERS > vol 69 n° 9 (September 2003) . - pp 1003 - 1010[article]