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Morphing linear features based on their entire structures / Min Deng in Transactions in GIS, vol 19 n° 5 (October 2015)  

Public [article]  inTransactions in GIS > vol 19 n° 5 (October 2015) . - pp 653 – 677 Titre : Morphing linear features based on their entire structures Type de document : Article/Communication Auteurs : Min Deng, Auteur ; Dongliang Peng, Auteur Année de publication : 2015 Article en page(s) : pp 653 – 677 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique [Termes IGN] algorithme de Douglas-Peucker [Termes IGN] arbre-B [Termes IGN] généralisation cartographique [Termes IGN] interpolation linéaire [Termes IGN] morphologie mathématique [Termes IGN] polyligne [Termes IGN] représentation cartographique [Termes IGN] triangulation de Delaunay Résumé : (auteur) In this article, a new morphing method is proposed for two linear features at different scales, based on their entire structures (MLBES in abbreviation). First, the bend structures of the linear features are identified by using a constrained Delaunay triangulation (CDT in abbreviation) model and represented by binary bend-structure trees. By matching the independent bends represented by the bend-structure trees, corresponding independent bends are obtained. These corresponding independent bends are further used to match their child bends based on hierarchical bend structures so that corresponding bends are obtained. On this basis, the two linear features are split into pairs of corresponding subpolylines by the start and end points of the corresponding bends. Second, structures of the corresponding subpolylines are identified by the Douglas-Peucker algorithm and represented by binary line generalization trees (BLG-trees in abbreviation). The corresponding subpolylines are split into smaller corresponding subpolylines by matching the nodes of the BLG-trees. Third, the corresponding points are identified by using the linear interpolation algorithm for every pair of corresponding subpolylines. Finally, straight-line trajectories are employed to generate a family of intermediate-scale linear features. By comparison with other methods, it is found that MLBES is accurate and efficient. Numéro de notice : A2015-682 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12111 En ligne : http://dx.doi.org/10.1111/tgis.12111 Format de la ressource électronique : Url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=78313 [article]

Triangulating social multimedia content for event localization using Flickr and Twitter / George Panteras in Transactions in GIS, vol 19 n° 5 (October 2015)  

Public [article]  inTransactions in GIS > vol 19 n° 5 (October 2015) . - pp 694 – 715 Titre : Triangulating social multimedia content for event localization using Flickr and Twitter Type de document : Article/Communication Auteurs : George Panteras, Auteur ; Sarah Wise, Auteur ; Xu Lu, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 694 – 715 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] analyse d'image numérique [Termes IGN] catastrophe naturelle [Termes IGN] détection de contours [Termes IGN] géopositionnement [Termes IGN] image Flickr [Termes IGN] orientation d'image [Termes IGN] réseau social [Termes IGN] Twitter [Termes IGN] zone d'intérêt Résumé : (auteur) The analysis of social media content for the extraction of geospatial information and event-related knowledge has recently received substantial attention. In this article we present an approach that leverages the complementary nature of social multimedia content by utilizing heterogeneous sources of social media feeds to assess the impact area of a natural disaster. More specifically, we introduce a novel social multimedia triangulation process that uses both Twitter and Flickr content in an integrated two-step process: Twitter content is used to identify toponym references associated with a disaster; this information is then used to provide approximate orientation for the associated Flickr imagery, allowing us to delineate the impact area as the overlap of multiple view footprints. In this approach, we practically crowdsource approximate orientations from Twitter content and use this information to orient Flickr imagery accordingly and identify the impact area through viewshed analysis and viewpoint integration. This approach enables us to avoid computationally intensive image analysis tasks associated with traditional image orientation, while allowing us to triangulate numerous images by having them pointed towards the crowdsourced toponym location. The article presents our approach and demonstrates its performance using a real-world wildfire event as a representative application case study. Numéro de notice : A2015-683 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12122 En ligne : http://dx.doi.org/10.1111/tgis.12122 Format de la ressource électronique : Url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=78316 [article]

Polygonal clustering analysis using multilevel graph-partition / Wanyi Wang in Transactions in GIS, vol 19 n° 5 (October 2015)  

Public [article]  inTransactions in GIS > vol 19 n° 5 (October 2015) . - pp 716 – 736 Titre : Polygonal clustering analysis using multilevel graph-partition Type de document : Article/Communication Auteurs : Wanyi Wang, Auteur ; Shihong Du, Auteur ; Zhou Guo, Auteur ; Liqun Luo, Auteur Année de publication : 2015 Article en page(s) : pp 716 – 736 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale [Termes IGN] analyse comparative [Termes IGN] analyse de groupement [Termes IGN] connexité (graphes) [Termes IGN] distance [Termes IGN] données spatiotemporelles [Termes IGN] figure géométrique [Termes IGN] groupe [Termes IGN] partition des données [Termes IGN] polygone [Termes IGN] similitude Résumé : (auteur) Existing methods of spatial data clustering have focused on point data, whose similarity can be easily defined. Due to the complex shapes and alignments of polygons, the similarity between non-overlapping polygons is important to cluster polygons. This study attempts to present an efficient method to discover clustering patterns of polygons by incorporating spatial cognition principles and multilevel graph partition. Based on spatial cognition on spatial similarity of polygons, four new similarity criteria (i.e. the distance, connectivity, size and shape) are developed to measure the similarity between polygons, and used to visually distinguish those polygons belonging to the same clusters from those to different clusters. The clustering method with multilevel graph-partition first coarsens the graph of polygons at multiple levels, using the four defined similarities to find clusters with maximum similarity among polygons in the same clusters, then refines the obtained clusters by keeping minimum similarity between different clusters. The presented method is a general algorithm for discovering clustering patterns of polygons and can satisfy various demands by changing the weights of distance, connectivity, size and shape in spatial similarity. The presented method is tested by clustering residential areas and buildings, and the results demonstrate its usefulness and universality. Numéro de notice : A2015-684 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12124 En ligne : http://dx.doi.org/10.1111/tgis.12124 Format de la ressource électronique : Url artticle Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=78325 [article]

Spatial information divergence: using global and local indices to compare geographical masks applied to crime data / Ourania Kounad in Transactions in GIS, vol 19 n° 5 (October 2015)  

Public [article]  inTransactions in GIS > vol 19 n° 5 (October 2015) . - pp 737 – 757 Titre : Spatial information divergence: using global and local indices to compare geographical masks applied to crime data Type de document : Article/Communication Auteurs : Ourania Kounad, Auteur ; Michael Leitner, Auteur Année de publication : 2015 Article en page(s) : pp 737 – 757 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications SIG [Termes IGN] analyse comparative [Termes IGN] cartographie thématique [Termes IGN] criminalité [Termes IGN] information géographique [Termes IGN] masque géographique [Termes IGN] système d'information géographique [Termes IGN] zonage (urbanisme) Résumé : (auteur) Advances in Geographic Information Science (GISc) and the increasing availability of location data have facilitated the dissemination of crime data and the abundance of crime mapping websites. However, data holders acknowledge that when releasing sensitive crime data there is a risk of compromising the victims' privacy. Hence, protection methodologies are primarily applied to the data to ensure that individual privacy is not violated. This article addresses one group of location protection methodologies, namely geographical masks that are applicable for crime data representations. The purpose is to identify which mask is the most appropriate for crime incident visualizations. A global divergence index (GDi) and a local divergence index (LDi) are developed to compare the effects that these masks have on the original crime point pattern. The indices calculate how dissimilar the spatial information of the masked data is from the spatial information of the original data in regards to the information obtained via spatial crime analysis. The results of the analysis show that the variable radius mask and the donut geomask should be primarily used for crime representations as they produce less spatial information divergence of the original crime point pattern than the alternative local random rotation mask and circular mask. Numéro de notice : A2015-685 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12125 En ligne : https://doi.org/10.1111/tgis.12125 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=78330 [article]

Construction of 3D volumetric objects for a 3D cadastral system / Shen Ying in Transactions in GIS, vol 19 n° 5 (October 2015)  

Public [article]  inTransactions in GIS > vol 19 n° 5 (October 2015) . - pp 758 – 779 Titre : Construction of 3D volumetric objects for a 3D cadastral system Type de document : Article/Communication Auteurs : Shen Ying, Auteur ; Renzhong Guo, Auteur ; Lin Li, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 758 – 779 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications SIG [Termes IGN] adjacence [Termes IGN] cadastre [Termes IGN] cadastre 3D [Termes IGN] modélisation 3D [Termes IGN] parcelle cadastrale [Termes IGN] reconstruction 3D [Termes IGN] topologie Résumé : (auteur) This article presents a new method to illustrate the feasibility of 3D topology creation. We base the 3D construction process on testing real cases of implementation of 3D parcels construction in a 3D cadastral system. With the utilization and development of dense urban space, true 3D geometric volume primitives are needed to represent 3D parcels with the adjacency and incidence relationship. We present an effective straightforward approach to identifying and constructing the valid volumetric cadastral object from the given faces, and build the topological relationships among 3D cadastral objects on-the-fly, based on input consisting of loose boundary 3D faces made by surveyors. This is drastically different from most existing methods, which focus on the validation of single volumetric objects after the assumption of the object's creation. Existing methods do not support the needed types of geometry/topology (e.g. non 2-manifold, singularities) and how to create and maintain valid 3D parcels is still a challenge in practice. We will show that the method does not change the faces themselves and faces in a given input are independently specified. Various volumetric objects, including non-manifold 3D cadastral objects (legal spaces), can be constructed correctly by this method, as will be shown from the results. Numéro de notice : A2015-686 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1111/tgis.12129 En ligne : http://dx.doi.org/10.1111/tgis.12129 Format de la ressource électronique : Url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=78332 [article]