Détail de l'auteur
Auteur E. Emiel Van Loon |
Documents disponibles écrits par cet auteur (2)



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)
![]()
[article]
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] GéovisualisationRésumé : (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
in Geoinformatica > vol 19 n° 1 (January - March 2015) . - pp 85 - 115[article]A probabilistic framework for representing and simulating uncertain environmental variables / Gerard B.M. Heuvelink in International journal of geographical information science IJGIS, vol 21 n° 5 (may 2007)
![]()
[article]
Titre : A probabilistic framework for representing and simulating uncertain environmental variables Type de document : Article/Communication Auteurs : Gerard B.M. Heuvelink, Auteur ; J. Brown, Auteur ; E. Emiel Van Loon, Auteur Année de publication : 2007 Article en page(s) : pp 497 - 513 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Information géographique
[Termes IGN] distribution, loi de
[Termes IGN] incertitude d'attribut
[Termes IGN] incertitude de position
[Termes IGN] incertitude des données
[Termes IGN] modèle stochastique
[Termes IGN] simulationRésumé : (Auteur) Understanding the limitations of environmental data is important for managing environmental systems effectively and for encouraging the responsible use of uncertain data. Explicit assessment of the uncertainties associated with environmental data, and their storage in a database, are therefore important. This paper presents a statistical framework for representing and simulating uncertain environmental variables. In general terms, an uncertain variable is completely specified by its probability distribution function (pdf). Pdfs are developed for objects with uncertain locations ('positional uncertainty') and uncertain attribute values ('attribute uncertainty'). Objects comprising multiple space-time locations are separated into 'rigid objects', where positional uncertainty cannot alter the internal geometry of the object, and 'deformable' objects, where positional uncertainty can vary between locations in one object. Statistical dependence is allowed between uncertainties in multiple locations in one object. The uncertainties associated with attribute values are also modelled with pdfs. The type and complexity of these pdfs depend upon the measurement scale and the space-time variability of the uncertain attribute. The framework is illustrated with examples. A prototype software tool for assessing uncertainties in environmental data, storing them within a database, and for generating realizations for use in Monte Carlo studies is also presented. Copyright Taylor & Francis Numéro de notice : A2007-133 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/13658810601063951 En ligne : https://doi.org/10.1080/13658810601063951 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28496
in International journal of geographical information science IJGIS > vol 21 n° 5 (may 2007) . - pp 497 - 513[article]Exemplaires(2)
Code-barres Cote Support Localisation Section Disponibilité 079-07031 RAB Revue Centre de documentation En réserve L003 Disponible 079-07032 RAB Revue Centre de documentation En réserve L003 Disponible