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Stacked space-time densities: a geovisualisation approach to explore dynamics of space use over time / Urška Demšar in Geoinformatica, vol 19 n° 1 (January - March 2015)  

Public [article]  inGeoinformatica > vol 19 n° 1 (January - March 2015) . - pp 85 - 115 Titre : Stacked space-time densities: a geovisualisation approach to explore dynamics of space use over time Type de document : Article/Communication Auteurs : Urška Demšar, Auteur ; Kevin Buchin, Auteur ; E. Emiel Van Loon, Auteur ; Judy Shamoun-Baranes, Auteur Année de publication : 2015 Article en page(s) : pp 85 - 115 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] agrégation spatiale [Termes IGN] agrégation temporelle [Termes IGN] analyse spatio-temporelle [Termes IGN] Aves [Termes IGN] cube espace-temps [Termes IGN] densité [Termes IGN] distance de propagation [Termes IGN] données spatiotemporelles [Termes IGN] estimation par noyau [Termes IGN] migration animale [Termes IGN] positionnement cinématique [Vedettes matières IGN] Géovisualisation Résumé : (auteur) Recent developments and ubiquitous use of global positioning devices have revolutionised movement ecology. Scientists are able to collect increasingly larger movement datasets at increasingly smaller spatial and temporal resolutions. These data consist of trajectories in space and time, represented as time series of measured locations for each tagged animal. Such data are analysed and visualised using methods for estimation of home range or utilisation distribution, which are often based on 2D kernel density in geographic space. These methods have been developed for much sparser and smaller datasets obtained through very high frequency (VHF) radio telemetry. They focus on the spatial distribution of measurement locations and ignore time and sequentiality of measurements. We present an alternative geovisualisation method for spatio-temporal aggregation of trajectories of tagged animals: stacked space-time densities. The method was developed to visually portray temporal changes in animal use of space using a volumetric display in a space-time cube. We describe the algorithm for calculation of stacked densities using four different decay functions, normally used in space use studies: linear decay, bisquare decay, Gaussian decay and Brownian decay. We present a case study, where we visualise trajectories of lesser black backed gulls, collected over 30 days. We demonstrate how the method can be used to evaluate temporal site fidelity of each bird through identification of two different temporal movement patterns in the stacked density volume: spatio-temporal hot spots and spatial-only hot spots. Numéro de notice : A2015-486 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1007/s10707-014-0207-5 Date de publication en ligne : 03/04/2014 En ligne : https://doi.org/10.1007/s10707-014-0207-5 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=77249 [article]

The technique of distance decayed visibility for forest landscape visualization / C. Kumsap in International journal of geographical information science IJGIS, vol 19 n° 6 (july 2005)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 19 n° 6 (july 2005) . - pp 723 - 744 Titre : The technique of distance decayed visibility for forest landscape visualization Type de document : Article/Communication Auteurs : C. Kumsap, Auteur ; F. Borne, Auteur ; D. Moss, Auteur Année de publication : 2005 Article en page(s) : pp 723 - 744 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes d'information géographique [Termes IGN] altération [Termes IGN] distance de propagation [Termes IGN] forêt [Termes IGN] paysage [Termes IGN] point d'appui [Termes IGN] système d'information géographique [Termes IGN] visualisation 3D Résumé : (Auteur) The paper discusses an approach known as 'distance-decayed visibility', implemented using GIS, to the composition of 3D scenes for static forest landscape visualization. The distance-decay concept is employed to model a spatial interaction in terms of visibility between any observation points and vegetations visible from those points. The vegetation visibility is measured in level of detail where high visibility uses high level of detail and vice versa. The interaction is modelled mathematically using an exponential decay function. The point distribution of projected models on a 3D scene is calculated in GIS to assign an appropriate value of 'visibility decay constant' to relate the distance from the observation point to the vegetations with the level of detail of the vegetations in the function. The advantages of the technique as measured against the quantitative benchmarks of rendering time and the number of polygons computed are addressed. Although the forest landscape of the study area consists of a large number of vegetation models, the technique helps to model the relation of vegetation visibility and viewing distance so realistically that the technique yields the visual quality of the result 3D scene visually and statistically comparable to the finest resolution scene. Numéro de notice : A2005-290 Affiliation des auteurs : non IGN Thématique : FORET/GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1080/13658810500104880 En ligne : https://doi.org/10.1080/13658810500104880 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27426 [article]

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Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-05061	RAB	Revue	Centre de documentation	En réserve L003	Disponible
079-05062	RAB	Revue	Centre de documentation	En réserve L003	Disponible