Paru le : 01/10/2003 ISBN/ISSN/EAN : 1365-8816 |
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Ajouter le résultat dans votre panierWavelets applied to simplification of digital terrain models / J.T. Bjorke in International journal of geographical information science IJGIS, vol 17 n° 7 (october 2003)
[article]
Titre : Wavelets applied to simplification of digital terrain models Type de document : Article/Communication Auteurs : J.T. Bjorke, Auteur ; S. Nilsen, Auteur Année de publication : 2003 Article en page(s) : pp 601 - 621 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] filtrage non linéaire
[Termes IGN] filtrage numérique d'image
[Termes IGN] modèle numérique de terrain
[Termes IGN] ondelette
[Termes IGN] seuillage d'imageRésumé : (Auteur) Wavelet thresholding is used to generate simplified terrain models. This nonlinear filtering technique is adaptive in the sense that the large wavelet coefficients in areas of high relief are kept, whereas all coefficients smaller than a threshold value, representing smooth areas, are thrown away. The degree of detail in the simplified model is controlled by the number of wavelet coefficients retained. Two different areas are analysed using this method. The experiments show the smoothing effect of the thresholding, and how the main terrain features survive as the threshold value increases. At large threshold values the method introduces blocking artifacts in the model. Numéro de notice : A2003-256 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1080/1365881031000135500 En ligne : https://doi.org/10.1080/1365881031000135500 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22551
in International journal of geographical information science IJGIS > vol 17 n° 7 (october 2003) . - pp 601 - 621[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 079-03071 RAB Revue Centre de documentation En réserve L003 Disponible 079-03072 RAB Revue Centre de documentation En réserve L003 Disponible A comparison of two methods to create tracks of moving objects: linear weighted distance and constrained random walk [distance linéaire pondérée et trajet aléatoire contraint] / E.A. Wentz in International journal of geographical information science IJGIS, vol 17 n° 7 (october 2003)
[article]
Titre : A comparison of two methods to create tracks of moving objects: linear weighted distance and constrained random walk [distance linéaire pondérée et trajet aléatoire contraint] Type de document : Article/Communication Auteurs : E.A. Wentz, Auteur ; A.F. Campbell, Auteur ; R. Houston, Auteur Année de publication : 2003 Article en page(s) : pp 623 - 645 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale
[Termes IGN] analyse comparative
[Termes IGN] distance pondérée
[Termes IGN] incertitude des données
[Termes IGN] objet mobile
[Termes IGN] positionnement cinématique
[Termes IGN] Simiiformes
[Termes IGN] trajectographie (positionnement)
[Termes IGN] trajet (mobilité)
[Termes IGN] variable aléatoireRésumé : (Auteur) As an object moves through space, it creates a track (or path) representing the object's past and present position and associated attributes. If data capture falls, then positions along the tracks are unknown. The particular problem we address in this paper is to create tracks of moving objects with missing data. We implement and test two techniques that create continuous tracks of two primate species (Ateles geoffroyi, the red spider monkey, and Cebus capucinus, the whitefaced capuchin). Continuous tracks were needed to calculate home range and to analyze daily ranging patterns for each species. Establishing continuous tracks of primates through field data alone, however, was impossible due to challenging field conditions. The results of the analysis using tracks with interpolated positions helped establish that Ateles tend to move directly to their destination while Cebus tended to follow a more wandering track. Numéro de notice : A2003-257 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1080/1365881031000135492 En ligne : https://doi.org/10.1080/1365881031000135492 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22552
in International journal of geographical information science IJGIS > vol 17 n° 7 (october 2003) . - pp 623 - 645[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 079-03071 RAB Revue Centre de documentation En réserve L003 Disponible 079-03072 RAB Revue Centre de documentation En réserve L003 Disponible Increasing the spatial resolution of agricultural land cover maps using a Hopfield neural network / A.J. Tatem in International journal of geographical information science IJGIS, vol 17 n° 7 (october 2003)
[article]
Titre : Increasing the spatial resolution of agricultural land cover maps using a Hopfield neural network Type de document : Article/Communication Auteurs : A.J. Tatem, Auteur ; H.G. Lewis, Auteur ; P.M. Atkinson, Auteur ; M.S. Nixon, Auteur Année de publication : 2003 Article en page(s) : pp 647 - 672 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] carte agricole
[Termes IGN] carte d'occupation du sol
[Termes IGN] classification par réseau neuronal
[Termes IGN] erreur moyenne quadratique
[Termes IGN] Grèce
[Termes IGN] image Landsat-TM
[Termes IGN] image satellite
[Termes IGN] incertitude géométrique
[Termes IGN] limite de résolution géométrique
[Termes IGN] occupation du sol
[Termes IGN] précision infrapixellaireRésumé : (Auteur) Land cover class composition of remotely sensed image pixels can be estimated using soft classification techniques increasingly available in many GIS packages. However, their output provides no indication of how such classes are distributed spatially within the instantaneous field of view represented by the pixel. Techniques that attempt to provide an improved spatial representation of land cover have been developed, but not tested on the difficult task of mapping from real satellite imagery. The authors investigated the use of a Hopfield neural network technique to map the spatial distributions of classes reliably using information of pixel composition determined from soft classification previously. The approach involved designing the energy function to produce a 'best guess' prediction of the spatial distribution of class components in each pixel. In previous studies, the authors described the application of the technique to target identification, pattern prediction and land cover mapping at the subpixel scale, but only for simulated imagery. We now show how the approach can be applied to Landsat Thematic Mapper (TM) agriculture imagery to derive accurate estimates of land cover and reduce the uncertainty inherent in such imagery. The technique was applied to Landsat TM imagery of smallscale agriculture in Greece and largescale agriculture near Leicester, UK. The resultant maps provided an accurate and improved representation of the land covers studied, with RMS errors for the Landsat imagery of the order of 0.1 in the new fine resolution map recorded. The results showed that the neural network represents a simple efficient tool for mapping land cover from operational satellite sensor imagery and can deliver requisite results and improvements over traditional techniques for the GIS analysis of pratical remotly sensed imagery at the sub pixel scale. Numéro de notice : A2003-258 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1080/1365881031000135519 En ligne : https://doi.org/10.1080/1365881031000135519 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22553
in International journal of geographical information science IJGIS > vol 17 n° 7 (october 2003) . - pp 647 - 672[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 079-03071 RAB Revue Centre de documentation En réserve L003 Disponible 079-03072 RAB Revue Centre de documentation En réserve L003 Disponible The discrete dynamics of small-scale spatial events: agent-based models of mobility in carnivals and street parades / Michael Batty in International journal of geographical information science IJGIS, vol 17 n° 7 (october 2003)
[article]
Titre : The discrete dynamics of small-scale spatial events: agent-based models of mobility in carnivals and street parades Type de document : Article/Communication Auteurs : Michael Batty, Auteur ; J. Desyllas, Auteur ; E. Duxbury, Auteur Année de publication : 2003 Article en page(s) : pp 673 - 697 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Analyse spatiale
[Termes IGN] analyse spatio-temporelle
[Termes IGN] densité
[Termes IGN] dynamique spatiale
[Termes IGN] mobilité urbaine
[Termes IGN] modèle mathématique
[Termes IGN] petite échelle
[Termes IGN] piéton
[Termes IGN] simulationRésumé : (Auteur) Small-scale spatial events are situations in which elements or objects vary in such a way that temporal dynamics are intrinsic to their representation and explanation. Some of the clearest examples involve local movement, from conventional traffic modeling to disaster evacuation where congestion, crowding, panic, and related safety issues are key features. We propose that such events can be simulated using new variants of pedestrian model, which embody ideas about how behavior emerges from the accumulated interactions between small-scale objects. We present a model in which the event space is first explored by agents using 'swarm intelligence'. Armed with information about the space, agents then move in unobstructed fashion to the event. Congestion and problems over safety are then resolved through introducing controls in an iterative fashion, rerunning the model until a 'safe solution' is reached. The model has been developed to simulate the effect of changing the route of the Notting Hill Carnival, an annual event held in west central London over 2 days in August each year. One of the key issues in using such simulation is how the process of modeling interacts with those who manage and control the event. As such, this changes the nature of the modeling problem from one where control and optimization is external to the model to one where it is intrinsic to the simulation. Numéro de notice : A2003-259 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article DOI : 10.1080/1365881031000135474 En ligne : https://doi.org/10.1080/1365881031000135474 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22554
in International journal of geographical information science IJGIS > vol 17 n° 7 (october 2003) . - pp 673 - 697[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 079-03071 RAB Revue Centre de documentation En réserve L003 Disponible 079-03072 RAB Revue Centre de documentation En réserve L003 Disponible Maximizing spatial congruence of observed and DEM-delineated overland flow networks / T.A. Endreny in International journal of geographical information science IJGIS, vol 17 n° 7 (october 2003)
[article]
Titre : Maximizing spatial congruence of observed and DEM-delineated overland flow networks Type de document : Article/Communication Auteurs : T.A. Endreny, Auteur ; E.F. Wood, Auteur Année de publication : 2003 Article en page(s) : pp 699 - 713 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] bassin hydrographique
[Termes IGN] congruence
[Termes IGN] modèle hydrographique
[Termes IGN] modèle numérique de terrainRésumé : (Auteur) Model simulated overland flow is traditionally routed by the terrainbased algorithms that read 90 to 10-m pixel data, yet observed flow is often influenced by submeter micro-terrain features. While sub-meter terrain maps are not available for most watersheds, routing algorithms that bifurcate flow through multiple pixel boundaries may function to match observed runoff patterns. This paper assesses the spatial congruence between observed overland flow from two agricultural hillslopes in New Jersey with 30-m pixel flowpaths predicted by five common routing algorithms known as D8, Multiple Flow, 2D-Lea, (a building block in DEMON), 2D-Jensen, and D-Infinity. The lowest congruence ratings were assigned to D8, which constrained flow to a single neighbour, and MF, which bifurcated flow into all neighbours lower in elevation. 2D-Lea and D-Infinity, algorithms that bifurcated flow to a maximum of two neighbours, achieved the highest accuracy rankings. Simple algorithm modifications that increased D8 bifurcation, and constrained MF bifurcation, resulted in congruence rankings that rivaled the more sophisticated 2D-Lea, 2D-Jensen, and D-Infinity results. These experiments support the use of flow bifurcation schemes that pass flow into a maximum of between two and three pixels when routing polluted runoff. Numéro de notice : A2003-260 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1080/1365881031000135483 En ligne : https://doi.org/10.1080/1365881031000135483 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22555
in International journal of geographical information science IJGIS > vol 17 n° 7 (october 2003) . - pp 699 - 713[article]Réservation
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