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Auteur Curtis E. Woodcock |
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Mapping and estimating land change between 2001 and 2013 in a heterogeneous landscape in West Africa: Loss of forestlands and capacity building opportunities / Hèou Maléki Badjana in International journal of applied Earth observation and geoinformation, vol 63 (December 2017)
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Titre : Mapping and estimating land change between 2001 and 2013 in a heterogeneous landscape in West Africa: Loss of forestlands and capacity building opportunities Type de document : Article/Communication Auteurs : Hèou Maléki Badjana, Auteur ; Pontus Olofsson, Auteur ; Curtis E. Woodcock, Auteur ; Jörg Helmschrot, Auteur ; et al., Auteur Année de publication : 2017 Article en page(s) : pp 15 - 23 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] Afrique occidentale
[Termes IGN] analyse diachronique
[Termes IGN] Bénin
[Termes IGN] changement d'occupation du sol
[Termes IGN] classification par forêts d'arbres décisionnels
[Termes IGN] déboisement
[Termes IGN] forêt
[Termes IGN] image Landsat-8
[Termes IGN] image Landsat-ETM+
[Termes IGN] image Landsat-OLI
[Termes IGN] logiciel libre
[Termes IGN] occupation du sol
[Termes IGN] Orfeo Tool Box
[Termes IGN] QGIS
[Termes IGN] TogoRésumé : (auteur) In West Africa, accurate classification of land cover and land change remains a big challenge due to the patchy and heterogeneous nature of the landscape. Limited data availability, human resources and technical capacities, further exacerbate the challenge. The result is a region that is among the more understudied areas in the world, which in turn has resulted in a lack of appropriate information required for sustainable natural resources management. The objective of this paper is to explore open source software and easy-to-implement approaches to mapping and estimation of land change that are transferrable to local institutions to increase capacity in the region, and to provide updated information on the regional land surface dynamics. To achieve these objectives, stable land cover and land change between 2001 and 2013 in the Kara River Basin in Togo and Benin were mapped by direct multitemporal classification of Landsat data by parameterization and evaluation of two machine-learning algorithms. Areas of land cover and change were estimated by application of an unbiased estimator to sample data following international guidelines. A prerequisite for all tools and methods was implementation in an open source environment, and adherence to international guidelines for reporting land surface activities. Findings include a recommendation of the Random Forests algorithm as implemented in Orfeo Toolbox, and a stratified estimation protocol − all executed in the QGIS graphical use interface. It was found that despite an estimated reforestation of 10,0727 ± 3480 ha (95% confidence interval), the combined rate of forest and savannah loss amounted to 56,271 ± 9405 ha (representing a 16% loss of the forestlands present in 2001), resulting in a rather sharp net loss of forestlands in the study area. These dynamics had not been estimated prior to this study, and the results will provide useful information for decision making pertaining to natural resources management, land management planning, and the implementation of the United Nations Collaborative Programme on Reducing Emissions from Deforestation and Forest Degradation in Developing Countries (UN-REDD). Numéro de notice : A2017-411 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.jag.2017.07.006 En ligne : https://doi.org/10.1016/j.jag.2017.07.006 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86298
in International journal of applied Earth observation and geoinformation > vol 63 (December 2017) . - pp 15 - 23[article]Resolution dependent errors in remote sensing of cultivated areas / M. Ozdogan in Remote sensing of environment, vol 103 n° 2 (30/07/2006)
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Titre : Resolution dependent errors in remote sensing of cultivated areas Type de document : Article/Communication Auteurs : M. Ozdogan, Auteur ; Curtis E. Woodcock, Auteur Année de publication : 2006 Article en page(s) : pp 203 - 217 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] analyse comparative
[Termes IGN] analyse de sensibilité
[Termes IGN] Californie (Etats-Unis)
[Termes IGN] Chine
[Termes IGN] cultures
[Termes IGN] distribution spatiale
[Termes IGN] erreur de classification
[Termes IGN] image Ikonos
[Termes IGN] limite de résolution géométrique
[Termes IGN] précision infrapixellaire
[Termes IGN] seuillage d'image
[Termes IGN] surface cultivée
[Termes IGN] variogrammeRésumé : (Auteur) Remote sensing has become a common and effective method for estimating the areal coverage of land cover classes. One class of particular interest is agriculture as area estimates of cultivated lands are important for purposes such as estimating yields or irrigation needs. The synoptic coverage of satellite imagery and the relative ease of automated analysis have led to widespread mapping of agriculture using remote sensing. The accuracy of area estimates derived from these maps is known to be related to the accuracy of the maps. However, even in the situation where the map is very accurate, errors in area estimates may occur. These errors result from the behavior of the distribution of subpixel proportions of cultivated areas, and how that behavior changes as a result of sensor spatial resolution and class definitions. The sensitivity of estimates of cultivated areas to sensor spatial resolution and to the choice of threshold used to define cultivated land is explored in six agriculturally distinct locations around the world. Using a beta model for the distribution of subpixel proportions that is parameterized using variograms, it is possible to model the distribution of subpixel proportions for any spatial resolution. When the spatial resolution is small with respect to the spatial structure of the landscape (as measured by the variogram range) use of any class definition threshold produces an estimate very close to the true area coverage. On the other hand, as the resolution becomes coarse in relation to the variogram range, the subpixel proportions are no longer concentrated at the extremes of the distribution and the difference between the estimated and the true area has greater sensitivity to the selected threshold used to define classes. Thus, for the cases examined here, both the resolution and the class definition threshold have a strong influence on area estimates. The spatial resolutions where errors can be large depend on landscape spatial structure, which can be quantified using variograms. The net effect is that for the same spatial resolution, some places will exhibit much larger errors in area estimates than others. For the site in the Anhui province of China, where agricultural fields are very small (0.07 ha on the average), area estimates are highly sensitive to class definition thresholds even at the relatively fine resolution of 45 m. Conversely, in California (USA) spatial resolutions as coarse as 500 m can be used to reliably estimate cultivated areas. Results also suggest that the proportion of the total area that is cultivated significantly influences the accuracy of area estimates. When the area proportion is low, the class definition threshold must also be low to achieve an accurate area estimate. Conversely, in areas dominated by agriculture, a very stringent class definition of cultivated lands is required for accurate area estimates. While explored in the context of estimation of cultivated areas, the findings presented here are generic to the problem of area estimation using remote sensing. Copyright Elsevier Numéro de notice : A2006-321 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2006.04.004 En ligne : https://doi.org/10.1016/j.rse.2006.04.004 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28045
in Remote sensing of environment > vol 103 n° 2 (30/07/2006) . - pp 203 - 217[article]Uncertainty and confidence in land cover classification using a hybrid classifier approach / W. Liu in Photogrammetric Engineering & Remote Sensing, PERS, vol 70 n° 8 (August 2004)
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Titre : Uncertainty and confidence in land cover classification using a hybrid classifier approach Type de document : Article/Communication Auteurs : W. Liu, Auteur ; Sucharita Gopal, Auteur ; Curtis E. Woodcock, Auteur Année de publication : 2004 Article en page(s) : pp 963 - 971 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] Amérique du nord
[Termes IGN] classification hybride
[Termes IGN] classification par arbre de décision
[Termes IGN] classification par réseau neuronal
[Termes IGN] image NOAA-AVHRR
[Termes IGN] incertitude des données
[Termes IGN] occupation du solRésumé : (Auteur) Traditional methods of land cover classification and mapping are limited in providing spatial data on the uncertainty of map labels. In this paper, we present a hybrid classifier approach using Decision Tree (DT) and ARTMAP neural network to providing confidence or uncertainty information via majority voting and other rules. The hybrid classifier is tested with AVHRR data to mapping land cover of North America. The two classifiers (DT and ARTMAP) tend to make predictive errors in different contexts. They show 68% agreement in classifying land cover of North America. A set of rules is developed to assign class labels for pixels where the two classifiers disagree. Levels of confidence in the hybrid classification derived from their individual voting (ARTmAP) and probability (DT) are used to assign confidence. The approach outlined in this paper produces two products a hybrid classification map as well as a confidence map based on the two classification schemes. The hybrid approach seems suitable to tackle a variety of classification problems in remote sensing and may ultimately aid map users in making more informed decisions. Numéro de notice : A2004-309 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.70.8.963 En ligne : https://doi.org/10.14358/PERS.70.8.963 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26836
in Photogrammetric Engineering & Remote Sensing, PERS > vol 70 n° 8 (August 2004) . - pp 963 - 971[article]Evaluation of the MODIS LAI at coniferous forest site in Finland / Y. Wang in Remote sensing of environment, vol 91 n° 1 (15/05/2004)
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Titre : Evaluation of the MODIS LAI at coniferous forest site in Finland Type de document : Article/Communication Auteurs : Y. Wang, Auteur ; Curtis E. Woodcock, Auteur ; et al., Auteur Année de publication : 2004 Article en page(s) : pp 114 - 127 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] analyse comparative
[Termes IGN] bande infrarouge
[Termes IGN] Finlande
[Termes IGN] forêt
[Termes IGN] image Landsat-ETM+
[Termes IGN] image Terra-MODIS
[Termes IGN] indice foliaire
[Termes IGN] Leaf Area Index
[Termes IGN] Pinophyta
[Termes IGN] segmentation d'imageRésumé : (Auteur) Leaf area index (LAI) collected in a needle-leaf forest site near Ruokolahti, Finland, during a field campaign in June 14-21, 2000, WA a, used to validate Moderate Resolution Imaging Spectroradionieter (MODIS) LAI algorithm. The field LAI data was first related to 30-m resolution Enhanced Thermal Mapper Plus (ETM+) images using empirical methods to create a high-resolution LAI map. The analysis of empirical approaches indicates that preliminary segmentation of the image followed by empirical modeling with the resulting patches, was an effective approach to developing an LAI validation surface. Comparison of the aggregated high-resolution LAI map and corresponding MODIS LAI retrievals suggests satisfactory behavior of the MODIS LAI algorithm although variation in MODIS LAI product is higher than expected. The MODIS algorithm, adjusted to high resolution, generally overestimates the LAI due to the influence of the understory vegetation. This indicates the need for improvements in the algorithm. An improved correlation between field measurements and the reduced simple ratio (RSR) suggests that the shortwave infrared (SWIR) band may provide valuable information for needle-leaf forests. Numéro de notice : A2004-238 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2004.02.007 En ligne : https://doi.org/10.1016/j.rse.2004.02.007 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26765
in Remote sensing of environment > vol 91 n° 1 (15/05/2004) . - pp 114 - 127[article]Multi-attribute vegetation maps of Forest Service lands in California supporting resource management decisions / Janet Franklin in Photogrammetric Engineering & Remote Sensing, PERS, vol 66 n° 10 (October 2000)
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Titre : Multi-attribute vegetation maps of Forest Service lands in California supporting resource management decisions Type de document : Article/Communication Auteurs : Janet Franklin, Auteur ; Curtis E. Woodcock, Auteur ; R. Warbington, Auteur Année de publication : 2000 Article en page(s) : 8 p. ; pp 1209 - 1217 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Bases de données localisées
[Termes IGN] aide à la décision
[Termes IGN] base de données localisées
[Termes IGN] Californie (Etats-Unis)
[Termes IGN] carte de la végétation
[Termes IGN] couvert végétal
[Termes IGN] flore locale
[Termes IGN] forêt
[Termes IGN] image Landsat-TM
[Termes IGN] incendie de forêt
[Termes IGN] inventaire forestier étranger (données)
[Termes IGN] risque naturelRésumé : (Auteur) Vegetation databases (digital maps) for USDA Forest Service lands in California (approximately 10 million ha) have been developed over the last decade using remote sensing and GIS methods. The databases are intended to support national and regional land-cover inventory and monitoring, interagency conservation and fire risk assessment, and wildlife habitat evaluation, as well as more traditional uses including land management planning and forest inventory within each National Forest. The digital maps are fine-scale relative to their extent, being derived from 30-m-resolution Landsat Thematic Mapper (TM) data and digital elevation models (DEMs). Map attributes included a vegetation life form class, a vegetation type, and canopy cover and size class estimates for forested polygons. Land-cover and vegetation type labels were more accurate than forest structure estimates. However, the mapping methodology is not static. New remote sensing data and analysis methods offer some promise to improve map attribute estimation. The database is being provided by the Forest Service to agency personnel, cooperators, and the public. Numéro de notice : A2000-259 Affiliation des auteurs : non IGN Thématique : FORET/GEOMATIQUE/INFORMATIQUE Nature : Article DOI : sans En ligne : https://www.asprs.org/wp-content/uploads/pers/2000journal/october/2000_oct_1209- [...] Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=21676
in Photogrammetric Engineering & Remote Sensing, PERS > vol 66 n° 10 (October 2000) . - 8 p. ; pp 1209 - 1217[article]Fuzzy set theory and thematic maps: accuracy assessment and area estimation / Curtis E. Woodcock in International journal of geographical information science IJGIS, vol 14 n° 2 (march 2000)PermalinkThe use of variograms in remote sensing : 1. Scene models and simulated images / Curtis E. Woodcock in Remote sensing of environment, vol 25 n° 3 (01/08/1988)PermalinkThe use of variograms in remote sensing : 2. Real digital images / Curtis E. Woodcock in Remote sensing of environment, vol 25 n° 3 (01/08/1988)PermalinkThe factor of scale in remote sensing / Curtis E. Woodcock in Remote sensing of environment, vol 21 n° 3 (01/04/1987)Permalink