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A new model for cloud tracking and analysis on satellite images / E. Guilbert in Geoinformatica, vol 11 n° 3 (September - November 2007)  

Public [article]  inGeoinformatica > vol 11 n° 3 (September - November 2007) . - pp 287 - 309 Titre : A new model for cloud tracking and analysis on satellite images Type de document : Article/Communication Auteurs : E. Guilbert, Auteur Année de publication : 2007 Article en page(s) : pp 287 - 309 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] algorithme snake [Termes IGN] analyse d'image numérique [Termes IGN] détection de contours [Termes IGN] données spatiotemporelles [Termes IGN] modèle mathématique [Termes IGN] modélisation spatio-temporelle [Termes IGN] morphologie mathématique [Termes IGN] nuage [Termes IGN] requête spatiotemporelle Résumé : (Auteur) The study of convective clouds is an important issue in weather analysis. Previous methods are based on shape matching and level set. In this paper, a method based on snake model is used for cloud tracking. Snakes are known to be more efficient than level set for contour detection however they do not handle topological changes. Therefore, geometrical criteria are introduced to characterize topological transformations. Geometrical techniques are then combined and inserted in the tracking algorithm to perform morphological operations. By applying this method, a history of the positions of the clouds is obtained. In a second stage, a data model is presented for cloud interrogation. Physical information is introduced and data are organized so that spatiotemporal queries can be performed. Results obtained with the tracking method on a real data set are presented and some query examples are given. Copyright Springer Numéro de notice : A2007-378 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1007/s10707-006-0008-6 En ligne : https://doi.org/10.1007/s10707-006-0008-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28741 [article]

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Higher order vagueness in geographical information: empirical geographical population of type N fuzzy sets / P. Fischer in Geoinformatica, vol 11 n° 3 (September - November 2007)  

Public [article]  inGeoinformatica > vol 11 n° 3 (September - November 2007) . - pp 311 - 330 Titre : Higher order vagueness in geographical information: empirical geographical population of type N fuzzy sets Type de document : Article/Communication Auteurs : P. Fischer, Auteur ; T. Cheng, Auteur ; J. Wood, Auteur Année de publication : 2007 Article en page(s) : pp 311 - 330 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] analyse discriminante [Termes IGN] classification floue [Termes IGN] détection de contours [Termes IGN] Ecosse [Termes IGN] géomorphologie locale [Termes IGN] imprécision géométrique [Termes IGN] sous ensemble flou Résumé : (Auteur) Fuzzy set theory has been suggested as a means for representing vague spatial phenomena, and is widely known for directly addressing some of the issues of vagueness such as the sorites paradox. Higher order vagueness is widely considered a necessary component of any theory of vagueness, but it is not so well known that it too is competently modelled by Type n Fuzzy sets. In this paper we explore the fuzzy representation of higher order vagueness with respect to spatial phenomena. Initially we relate the arguments on philosophical vagueness to Type n Fuzzy sets. As an example, we move on to an empirical generation of spatial Type 2 Fuzzy sets examining the spatial extent of mountain peaks in Scotland. We show that the Type 2 Fuzzy sets can be populated by using alternative parameterisations of a peak detection algorithm. Further ambiguities could also be explored using other parameters of this and other algorithms. We show some novel answers to interrogations of the mountain peaks of Scotland. The conclusion of this work is that higher order vagueness can be populated for Type 2 and higher fuzzy sets. It does not follow that it is always necessary to examine these higher order uncertainties, but a possible advantage in terms of the results of spatial inquiry is demonstrated. Copyright Springer Numéro de notice : A2007-379 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1007/s10707-006-0009-5 En ligne : https://doi.org/10.1007/s10707-006-0009-5 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28742 [article]

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Unified hybrid terrain representation based on local convexifications / M. Bóo in Geoinformatica, vol 11 n° 3 (September - November 2007)  

Public [article]  inGeoinformatica > vol 11 n° 3 (September - November 2007) . - pp 331 - 357 Titre : Unified hybrid terrain representation based on local convexifications Type de document : Article/Communication Auteurs : M. Bóo, Auteur ; M. Amor, Auteur ; Jürgen Döllner, Auteur Année de publication : 2007 Article en page(s) : pp 331 - 357 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] imprécision géométrique [Termes IGN] intégration de données [Termes IGN] maillage par triangles [Termes IGN] modèle numérique de terrain [Termes IGN] relation topologique [Termes IGN] résolution multiple [Termes IGN] tessellation [Termes IGN] Triangulated Irregular Network Résumé : (Auteur) Hybrid digital terrain models represent an effective framework to combine and integrate terrain data with different topology and resolution. Cartographic digital terrain models typically are constituted by regular grid data and can be refined by adding locally TINs that represent morphologically complex terrain parts. Direct rendering of both data sets to visualize the digital terrain model would generate geometric discontinuities as the meshes are disconnected. In this paper we present a new meshing scheme for hybrid terrain representations. High quality models without discontinuities are generated as the different representations are softly joined through an adaptive tessellation procedure. Due to the complexity of the algorithms involved in the tessellation procedure, we propose a mixed strategy where part of the information is pre-computed and efficiently encoded. This way, for rendering the model, the tessellation information has to be decoded and only additional simple operations have to be performed. Copyright Springer Numéro de notice : A2007-380 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1007/s10707-006-0003-y En ligne : https://doi.org/10.1007/s10707-006-0003-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28743 [article]

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Computation of random errors in digital terrain models / J. Bjorke in Geoinformatica, vol 11 n° 3 (September - November 2007)  

Public [article]  inGeoinformatica > vol 11 n° 3 (September - November 2007) . - pp 359 - 382 Titre : Computation of random errors in digital terrain models Type de document : Article/Communication Auteurs : J. Bjorke, Auteur ; S. Nilsen, Auteur Année de publication : 2007 Article en page(s) : pp 359 - 382 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques [Termes IGN] analyse comparative [Termes IGN] erreur aléatoire [Termes IGN] filtrage du bruit [Termes IGN] géostatistique [Termes IGN] modèle numérique de terrain [Termes IGN] rééchantillonnage [Termes IGN] sondeur multifaisceaux [Termes IGN] Triangulated Irregular Network [Termes IGN] variogramme Résumé : (Auteur) Geostatistical methods make it possible to estimate the random errors in digital terrain models (DTMs) from one single set of measurements. After average interpolating trend removal, the error is derived from the variogram of the residual data set. This method is compared with a procedure that uses triangulation and resampling of two overlapping DTMs for extracting the error component. Eighteen small areas measured with a multibeam echo sounder are selected for the comparison. In the experiment the two methods come out with similar values for the random error. A by-product of the experiment is the development of a model for the average noise reduction caused by resampling of triangle models (TINs). The method we apply for the trend computation has time complexity O(n). Since the noise computation only requires the part of the variogram close to the origin, it is possible to formulate the computation of the random error in DTMs in O(n) time. Copyright Springer Numéro de notice : A2007-381 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1007/s10707-006-0012-x En ligne : https://doi.org/10.1007/s10707-006-0012-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28744 [article]

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Weight-proportional space partitioning using adaptative Voronoi diagrams / R. Reitsma in Geoinformatica, vol 11 n° 3 (September - November 2007)  

Public [article]  inGeoinformatica > vol 11 n° 3 (September - November 2007) . - pp 383 - 405 Titre : Weight-proportional space partitioning using adaptative Voronoi diagrams Type de document : Article/Communication Auteurs : R. Reitsma, Auteur ; S. Trubin, Auteur ; E. Mortensen, Auteur Année de publication : 2007 Article en page(s) : pp 383 - 405 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] arbre quadratique [Termes IGN] décomposition d'image [Termes IGN] diagramme de Voronoï [Termes IGN] données maillées [Termes IGN] itération [Termes IGN] optimisation (mathématiques) [Termes IGN] partitionnement [Termes IGN] pondération Résumé : (Auteur) Traditional application of Voronoi diagrams for space partitioning results in Voronoi regions, each with a specific area determined by the generators’ relative locations and weights. Particularly in the area of information space (re)construction, however, there is a need for inverse solutions; i.e., finding weights that result in regions with predefined area ratios. In this paper, we formulate an adaptive Voronoi solution and propose a raster-based optimization method for finding the associated weight set. The solution consists of a combination of simple, fixed-point iteration with an optional spatial resolution refinement along the regions’ boundaries using quadtree decomposition. We present the corresponding algorithm and its complexity analysis. The method is successfully tested on a series of ideal–typical cases and the interactions between the adaptive technique and boundary resolution refinement are explored and assessed. Numéro de notice : A2007-382 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1007/s10707-006-0006-8 En ligne : https://doi.org/10.1007/s10707-006-0006-8 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28745 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
057-07031	RAB	Revue	Centre de documentation	En réserve L003	Disponible