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Using quadtree segmentation to support error modelling in categorical raster data / S. De Bruin in International journal of geographical information science IJGIS, vol 18 n° 2 (march 2004)  

Public [article]  inInternational journal of geographical information science IJGIS > vol 18 n° 2 (march 2004) . - pp 151 - 168 Titre : Using quadtree segmentation to support error modelling in categorical raster data Type de document : Article/Communication Auteurs : S. De Bruin, Auteur ; A.J. de Wit, Auteur Année de publication : 2004 Article en page(s) : pp 151 - 168 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Systèmes d'information géographique [Termes IGN] arbre quadratique [Termes IGN] carte d'occupation du sol [Termes IGN] données maillées [Termes IGN] hétérogénéité [Termes IGN] modèle d'erreur [Termes IGN] précision de la classification [Termes IGN] simulation [Termes IGN] système d'information géographique [Termes IGN] variogramme Résumé : (Auteur) This paper explores the use of quadtree segmentation of a land-cover map to improve error modelling by (1) accounting for variation in classification accuracy among differently sized homogeneous map regions and (2) improving the statistical properties of map realizations generated by sequential indicator simulation (SIS). The latter was accomplished by locating the first simulation nodes -which affect many subsequent local simulations- within the largest quadtree leaves. These represent the largest homogeneous and hypothetically most accurately classified areas on the map. A case study showed that, indeed, the overall accuracy of the land-cover map increased with the quadtree leaf size, ranging from 67% for single cells in heterogeneous areas to 98% for homogeneous blocks of 256 cells. A map of the prior probability of each land-cover class was prepared on the basis of quadtree level-specific confusion matrices. Next, two unconditional SIS algorithms were used to generate sets of 50 realizations of the map, thereby accounting for spatial continuity of the residuals between indicator-transformed reference data and the priors. The proposed quadtree-guided SIS outperformed the more common multiple-steps method as judged by the reproduction of target proportions of map categories, class-specific accuracy levels and variogram reproduction. Numéro de notice : A2004-040 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE/INFORMATIQUE Nature : Article DOI : 10.1080/13658810310001629600 En ligne : https://doi.org/10.1080/13658810310001629600 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26568 [article]

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Code-barres	Cote	Support	Localisation	Section	Disponibilité
079-04021	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Monitoring of land use and crop growth conditions in Europe / G.J.A. Nieuwenhuis (01/09/1998)  

Public contenu dans ISPRS Commission 7 Symposium Resource and environmental monitoring 1996-2000 / Gabor Remetey-Fulopp (1998)   Titre : Monitoring of land use and crop growth conditions in Europe Type de document : Article/Communication Auteurs : G.J.A. Nieuwenhuis, Auteur ; Caspar A. Mücher, Auteur ; A.J. de Wit, Auteur Editeur : International Society for Photogrammetry and Remote Sensing ISPRS Année de publication : 01/09/1998 Conférence : ISPRS 1998, Commission 7 symposium on Resource and environmental monitoring 01/09/1998 04/09/1998 Budapest Hongrie OA Proceedings archives Importance : pp 143 - 150 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] agriculture [Termes IGN] blé (céréale) [Termes IGN] cultures [Termes IGN] évapotranspiration [Termes IGN] image NOAA-AVHRR [Termes IGN] indice de végétation [Termes IGN] Normalized Difference Vegetation Index [Termes IGN] surveillance agricole Résumé : (Auteur) A pilot study has been performed to map land cover for selected regions of Europe using multi-temporal NOAA/AVHRR satellite images. Based on the classification results the meaning of a 1-km land cover database at the European scale for agricultural and environmental applications has been illustrated. In a recent study for the Space Applications Institute (SAI) of the Joint Research Centre (JRC, Ispra) the integrative use of high and low resolution satellite data and crop growth models have been studied by SC-DLO. Vegetation indices as derived from both high and low resolution satellite data were used to estimate crop parameters. Especially if the actual situation deviates considerably from the mean situation, more realistic yield figures were obtained. Evapotranspiration maps have been composed using both satellite systems. In general areal patterns as obtained with high and low resolution satellite data were in agreement with each other. This means that such images are highly relevant to detect alarming situations concerning crop water supply during the growing season. A quantitative analysis should be further elaborated, integrating satellite observations and crop growth model simulations. Numéro de notice : C1998-037 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Communication DOI : sans En ligne : https://goobi.tib.eu/viewer/image/1669065049/166/ Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=65761