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Trajectory Box Plot: a new pattern to summarize movements / Laurent Etienne in International journal of geographical information science IJGIS, vol 30 n° 5-6 (May - June 2016)
[article]
Titre : Trajectory Box Plot: a new pattern to summarize movements Type de document : Article/Communication Auteurs : Laurent Etienne, Auteur ; Thomas Devogele , Auteur ; M. Buchin, Auteur ; Gavin McArdle, Auteur Année de publication : 2016 Article en page(s) : pp 835 - 853 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale
[Termes IGN] analyse spatio-temporelle
[Termes IGN] boîte à moustaches
[Termes IGN] calcul d'itinéraire
[Termes IGN] distance de Fréchet
[Termes IGN] modèle numérique de déplacement
[Termes IGN] objet mobile
[Termes IGN] trajet (mobilité)Résumé : (Auteur) Nowadays, an abundance of sensors are used to collect very large datasets of moving objects. The movement of these objects can be analysed by identifying common routes. For this, a cluster of trajectories must be defined and the pattern of each cluster discovered. In this article, we introduce a new pattern, called the Trajectory Box Plot (TBP), to summarize a set of trajectories following the same route. The TBP is an extension of the well-known descriptive statistics Box Plot concept. Each TBP is described by a median trajectory, a 3D box and a 3D fence. The median trajectory depicts the typical movement of mobile objects. The box and the fences (whiskers) describe the spatial and temporal spreading around the central tendency. TBPs are useful to summarize and analyse trajectory streams, understand their spatio-temporal density and detect outliers. In this article, visual analysis highlights how the TBP pattern effectively describes how the density of trajectory clusters change over time. Numéro de notice : A2016-285 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/13658816.2015.1081205 En ligne : https://doi.org/10.1080/13658816.2015.1081205 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80864
in International journal of geographical information science IJGIS > vol 30 n° 5-6 (May - June 2016) . - pp 835 - 853[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 079-2016032 RAB Revue Centre de documentation En réserve L003 Disponible 079-2016031 RAB Revue Centre de documentation En réserve L003 Disponible Correction of terrestrial LiDAR intensity channel using Oren–Nayar reflectance model: An application to lithological differentiation / Dario Carrea in ISPRS Journal of photogrammetry and remote sensing, vol 113 (March 2016)
[article]
Titre : Correction of terrestrial LiDAR intensity channel using Oren–Nayar reflectance model: An application to lithological differentiation Type de document : Article/Communication Auteurs : Dario Carrea, Auteur ; Antonio Abellan, Auteur ; Florian Humair, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 17 - 29 Note générale : bibliothèque Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] angle d'incidence
[Termes IGN] correction d'image
[Termes IGN] distance euclidienne
[Termes IGN] données lidar
[Termes IGN] réflectance du sol
[Termes IGN] semis de points
[Termes IGN] télémétrie laser terrestre
[Termes IGN] test de performanceRésumé : (auteur) Ground-based LiDAR has been traditionally used for surveying purposes via 3D point clouds. In addition to XYZ coordinates, an intensity value is also recorded by LiDAR devices. The intensity of the backscattered signal can be a significant source of information for various applications in geosciences.
Previous attempts to account for the scattering of the laser signal are usually modelled using a perfect diffuse reflection. Nevertheless, experience on natural outcrops shows that rock surfaces do not behave as perfect diffuse reflectors. The geometry (or relief) of the scanned surfaces plays a major role in the recorded intensity values.
Our study proposes a new terrestrial LiDAR intensity correction, which takes into consideration the range, the incidence angle and the geometry of the scanned surfaces. The proposed correction equation combines the classical radar equation for LiDAR with the bidirectional reflectance distribution function of the Oren–Nayar model. It is based on the idea that the surface geometry can be modelled by a relief of multiple micro-facets. This model is constrained by only one tuning parameter: the standard deviation of the slope angle distribution (σslope) of micro-facets.
Firstly, a series of tests have been carried out in laboratory conditions on a 2 m2 board covered by black/white matte paper (perfect diffuse reflector) and scanned at different ranges and incidence angles. Secondly, other tests were carried out on rock blocks of different lithologies and surface conditions. Those tests demonstrated that the non-perfect diffuse reflectance of rock surfaces can be practically handled by the proposed correction method.
Finally, the intensity correction method was applied to a real case study, with two scans of the carbonate rock outcrop of the Dents-du-Midi (Swiss Alps), to improve the lithological identification for geological mapping purposes. After correction, the intensity values are proportional to the intrinsic material reflectance and are independent from range, incidence angle and scanned surface geometry. The corrected intensity values significantly improve the material differentiation.Numéro de notice : A2016-532 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2015.12.004 En ligne : https://doi.org/10.1016/j.isprsjprs.2015.12.004 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81616
in ISPRS Journal of photogrammetry and remote sensing > vol 113 (March 2016) . - pp 17 - 29[article]Impact de l’anisotropie du milieu dans les études de profilage géographique / Marie Trotta in Revue internationale de géomatique, vol 25 n° 4 (octobre - décembre 2015)
[article]
Titre : Impact de l’anisotropie du milieu dans les études de profilage géographique Type de document : Article/Communication Auteurs : Marie Trotta, Auteur ; Cécile Deprez, Auteur ; Jean-Paul Donnay, Auteur Année de publication : 2015 Article en page(s) : pp 561 - 579 Note générale : Bibliographie Langues : Français (fre) Descripteur : [Vedettes matières IGN] Analyse spatiale
[Termes IGN] anisotropie
[Termes IGN] Belgique
[Termes IGN] densité d'information
[Termes IGN] distance euclidienne
[Termes IGN] données statistiques
[Termes IGN] origine - destination
[Termes IGN] répartition géographique
[Termes IGN] réseau routier
[Termes IGN] zone géographiqueRésumé : (auteur) Cet article a pour objectif d’évaluer le biais introduit par l’usage de la distance euclidienne dans le cadre d’analyses de profilage géographique. Elle procède par une comparaison des distances routières et euclidiennes calculées sur près de 1 000 couples d’origines-destinations (sites de crimes – point d’ancrage du criminel) issus de la base de données de la police fédérale belge. Les comparaisons sont différenciées selon la densité du réseau de voirie (milieux rural et urbanisé) et les paramètres statistiques des distributions résultantes sont exploités dans l’application du modèle de décroissance avec la distance, principal outil de profilage géographique. Numéro de notice : A2015-927 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.3166/RIG.25.561-579 Date de publication en ligne : 24/06/2016 En ligne : https://doi.org/10.3166/RIG.25.561-579 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=79729
in Revue internationale de géomatique > vol 25 n° 4 (octobre - décembre 2015) . - pp 561 - 579[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 047-2015041 RAB Revue Centre de documentation En réserve L003 Disponible An alternative method to constructing time cartograms for the visual representation of scheduled movement data / Rehmat Ullah in Journal of maps, vol 11 n° 4 ([01/08/2015])
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Titre : An alternative method to constructing time cartograms for the visual representation of scheduled movement data Type de document : Article/Communication Auteurs : Rehmat Ullah, Auteur ; Menno-Jan Kraak, Auteur Année de publication : 2015 Article en page(s) : pp 674 - 687 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cartographie thématique
[Termes IGN] carte thématique
[Termes IGN] cartogramme
[Termes IGN] distance kilométrique
[Termes IGN] durée de trajet
[Termes IGN] méthode des moindres carrés
[Termes IGN] migration pendulaire
[Termes IGN] Pays-Bas
[Termes IGN] réseau ferroviaire
[Termes IGN] transformation affineRésumé : (auteur) In a cartogram, the map elements are purposely modified with respect to an attribute. A time cartogram is a type of cartogram in which the geographic-distance between locations is replaced by a time-related attribute such as travelling-time, deforming the geography accordingly. This study concentrates on centred time cartograms that visualize travelling-times from a fixed starting location to other locations in the region. Several methods to construct time cartograms have been proposed, however these methods are not entirely satisfactory. In particular, none of them describes how to deform both the network and the map's boundaries based on travelling-times, which is necessary to maintain recognizability. In many cases, homeomorphism and topology are not maintained. The resultant maps from such methods are highly deformed and are difficult to read. Some of these methods are computationally demanding, while the procedures of others are not fully described. We present a method to construct time cartograms for the visual representation of scheduled movement data using the Dutch railways network as a case study. The method was developed by approaching the construction of time cartograms as a two-step process. In the first step, vector calculus is used to displace the train stations according to travelling-times from a fixed starting station. In the second step, moving-least-squares based affine deformation is applied to deform the railroads and the map's boundaries accordingly. To enhance understanding, concentric circles are drawn from the starting station to depict travelling-times. The method maintains homeomorphism and topology and yields time cartograms that are easily recognizable. Numéro de notice : A2015-541 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/17445647.2014.935502 En ligne : https://doi.org/10.1080/17445647.2014.935502 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=77518
in Journal of maps > vol 11 n° 4 [01/08/2015] . - pp 674 - 687[article]Very high resolution image matching based on local features and k-means clustering / Amin Sedaghat in Photogrammetric record, vol 30 n° 150 (June - August 2015)
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Titre : Very high resolution image matching based on local features and k-means clustering Type de document : Article/Communication Auteurs : Amin Sedaghat, Auteur ; Hamid Ebadi, Auteur Année de publication : 2015 Article en page(s) : pp 166 - 186 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] appariement d'images
[Termes IGN] distance euclidienne
[Termes IGN] extraction de traits caractéristiques
[Termes IGN] image à très haute résolution
[Termes IGN] partitionnement
[Termes IGN] primitive géométriqueRésumé : (Auteur) Image matching is a critical process in photogrammetry and remote sensing. Automatic and reliable feature matching using well-distributed points in very high resolution images is a difficult task due to significant relief displacement caused by tall buildings and ground relief. In this paper a robust and efficient image-matching approach is proposed, consisting of two main steps. In the first step, three sets of local features – Harris points, UR-SIFT and MSER – are extracted over the entire image. A SIFT (scale-invariant feature transform) descriptor is then created for each extracted feature, and an initial cross-matching verification is performed using the Euclidean distance between feature descriptors. In the second step, an approach based on k-means clustering is performed to achieve accurate matching without mismatched features, followed by a consistency check using a local affine transformation model for each cluster. The proposed method is successfully applied to matching various aerial and satellite images and the results demonstrate its robustness and capability. Numéro de notice : A2015-366 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1111/phor.12101 Date de publication en ligne : 29/06/2015 En ligne : https://doi.org/10.1111/phor.12101 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76908
in Photogrammetric record > vol 30 n° 150 (June - August 2015) . - pp 166 - 186[article]Réservation
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