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Assessing the effects of human-induced land degradation in the former homelands of northern South Africa with a 1 km AVHRR NDVI time-series / K.J. Wessels in Remote sensing of environment, vol 91 n° 1 (15/05/2004)
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Titre : Assessing the effects of human-induced land degradation in the former homelands of northern South Africa with a 1 km AVHRR NDVI time-series Type de document : Article/Communication Auteurs : K.J. Wessels, Auteur ; S.D. Prince, Auteur ; et al., Auteur Année de publication : 2004 Article en page(s) : pp 47 - 67 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] Afrique du sud (état)
[Termes IGN] analyse comparative
[Termes IGN] dégradation de l'environnement
[Termes IGN] érosion hydrique
[Termes IGN] image Landsat-TM
[Termes IGN] image NOAA-AVHRR
[Termes IGN] Normalized Difference Vegetation Index
[Termes IGN] précipitation
[Termes IGN] production agricole
[Termes IGN] série temporelle
[Termes IGN] surface cultivéeRésumé : (Auteur) There is a pressing need for an objective, repeatable, systematic and spatially explicit measure of land degradation. In northeastern South Africa (SA), there are large areas of the former homelands that are widely regarded as degraded. A time-series of seasonally integrated 1 km, Advanced Very High Resolution Radiometer (AVHRR) normalized difference vegetation index (NDVI) data was used to compare degraded rangelands [mapped by the National Land Cover (NLC) using Landsat Thematic Mapper (TM) imagery] to nondegraded rangelands within the same land capability units (LCUs). Nondegraded and degraded areas in the same LCU (paired areas) were compared by: (i) testing for differerences in spatial mean NDVI values, (ii) calculating the relative degradation impact (RDI) as the difference between the spatial mean NDVI values of paired areas expressed as a percentage of nondegraded mean value, (iii) investigating the relationship between RDI and rainfall and (iv) comparing the resilience and stability of paired areas in response to natural variations in rainfall. The NDVI of degraded areas was significantly lower for most of the LCUs. Relative degradation impacts (RDI) across all LCUs ranged from 1% to 20% with an average of 9%. Although NDVI was related to rainfall, RDI was not. Degraded areas were no less stable or resilient than nondegraded. However, the productivity of degraded areas, i.e., the forage production per unit rainfall, was consistently lower than nondegraded areas, even within years of above normal rainfall. The results indicate that there has not been a catastrophic reduction in ecosystem function within degraded areas. Instead, degradation impacts were reflected as reductions in productivity that varied along a continuum from slight to severe, depending on the specific LCU. Numéro de notice : A2004-236 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2004.02.005 En ligne : https://doi.org/10.1016/j.rse.2004.02.005 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26763
in Remote sensing of environment > vol 91 n° 1 (15/05/2004) . - pp 47 - 67[article]An integrated approach for landslide susceptibility mapping using remote sensing and GIS / S. Sarkar in Photogrammetric Engineering & Remote Sensing, PERS, vol 70 n° 5 (May 2004)
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Titre : An integrated approach for landslide susceptibility mapping using remote sensing and GIS Type de document : Article/Communication Auteurs : S. Sarkar, Auteur ; D.P. Kanungo, Auteur Année de publication : 2004 Article en page(s) : pp 617 - 625 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] cartographie des risques
[Termes IGN] classification
[Termes IGN] couche thématique
[Termes IGN] données de terrain
[Termes IGN] effondrement de terrain
[Termes IGN] Himalaya
[Termes IGN] image IRS
[Termes IGN] risque naturel
[Termes IGN] système d'information géographiqueRésumé : (Auteur) A methodology for landslide susceptibility mapping using an integrated remote sensing and GIS approach is presented. A part of the Darjeeling Himalaya was selected for the model execution. IRS satellite data, topographic maps, field data, and other informative maps were used as inputs to the study. Important terrain factors, contributing to landslide occurrences in the region, were identified and corresponding thematic data layers were generated. These data layers represent the geological, topographical, and hydrological conditions of the terrain. A numerical rating scheme for the factors was developed for spatial data analysis in a GIS. The resulting landslide susceptibility map delineates the area into different zones of four relative susceptibility classes: high, moderate, low, and very low. The susceptibility map was validated by correlating the landslide frequencies of different classes. This has shown a close agreement with the existing field instability condition. The effectiveness of the map was also confirmed by the high statistically significant value of a chi-square test. Numéro de notice : A2004-182 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.70.5.617 En ligne : https://doi.org/10.14358/PERS.70.5.617 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26709
in Photogrammetric Engineering & Remote Sensing, PERS > vol 70 n° 5 (May 2004) . - pp 617 - 625[article]Classification of contamination in salt marsh plant using hyperspectral reflectance / M.D. Wilson in IEEE Transactions on geoscience and remote sensing, vol 42 n° 5 (May 2004)
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Titre : Classification of contamination in salt marsh plant using hyperspectral reflectance Type de document : Article/Communication Auteurs : M.D. Wilson, Auteur ; S.L. Ustin, Auteur ; D.M. Rocke, Auteur Année de publication : 2004 Article en page(s) : pp 1088 - 1095 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] agriculture
[Termes IGN] analyse comparative
[Termes IGN] contamination
[Termes IGN] image hyperspectrale
[Termes IGN] marais salé
[Termes IGN] pétrole
[Termes IGN] pollution des sols
[Termes IGN] réflectance spectrale
[Termes IGN] réflectance végétaleRésumé : (Auteur) In this paper, we compare the classification effectiveness of two relatively new techniques on data consisting of leaf-level reflectance from five species of salt marsh and two species of crop plants (in four experiments) that have been exposed to varying levels of different heavy metal or petroleum toxicity, with a control treatment for each experiment. If these methodologies work well on leaf-level data, then there is hope that they will also work well on data from air- and spaceborne platforms. The classification methods compared were support vector classification (SVC) of exposed and nonexposed plants based on the spectral reflectance data, and partial least squares compression of the spectral reflectance data followed by classification using logistic discrimination (PLSALD). The statistic we used to compare the effectiveness of the methodologies was the leave-one-out cross-validation estimate of the prediction error. Our results suggest that both techniques perform reasonably well, but that SVC was superior to PLS/LD for use on hyperspectral data and it is worth exploring as a technique for classifying heavy-metal or petroleum exposed plants for the more complicated data from airand spaceborne sensors. Numéro de notice : A2004-195 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2003.823278 En ligne : https://doi.org/10.1109/TGRS.2003.823278 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26722
in IEEE Transactions on geoscience and remote sensing > vol 42 n° 5 (May 2004) . - pp 1088 - 1095[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 065-04051 RAB Revue Centre de documentation En réserve L003 Disponible Seeing the trees in the forest: Using Lidar and multispectral data fusion with local filtering and variable window size for estimating tree height / S.C. Pospecu in Photogrammetric Engineering & Remote Sensing, PERS, vol 70 n° 5 (May 2004)
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Titre : Seeing the trees in the forest: Using Lidar and multispectral data fusion with local filtering and variable window size for estimating tree height Type de document : Article/Communication Auteurs : S.C. Pospecu, Auteur ; R. Wynne, Auteur Année de publication : 2004 Article en page(s) : pp 589 - 604 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] couvert forestier
[Termes IGN] données lidar
[Termes IGN] estimation statistique
[Termes IGN] feuillu
[Termes IGN] fusion d'images
[Termes IGN] hauteur des arbres
[Termes IGN] identification automatique
[Termes IGN] image multibande
[Termes IGN] modèle de régression
[Termes IGN] Pinus (genre)Résumé : (Auteur) The main study objective was to develop robust processing and analysis techniques to facilitate the use of small-footprint lidar data for estimating plot-level tree height by measuring individual trees identifiable on the three-dimensional lidar surface. Lidar processing techniques included data fusion with multispectral optical data and local filtering with both square and circular windows of variable size. The lidar system used for this study produced an average footprint of 0.65 m and an average distance between laser shots of 0.7 m. The lidar data set was acquired over deciduous and coniferous stands with settings typical of the southeastern United States. The lidar-derived tree measurements were used with regression models and cross-validation to estimate tree height on 0.017-ha plots. For the pine plots, lidar measurements explained 97 percent of the variance associated with the mean height of dominant trees. For deciduous plots, regression models explained 79 percent of the mean height variance for dominant trees. Filtering for local maximum with circular windows gave better fitting models for pines, while for deciduous trees, filtering with square windows provided a slightly better model fit. Using lidar and optical data fusion to differentiate between forest types provided better results for estimating average plot height for pines. Estimating tree height for deciduous plots gave superior results without calibrating the search window size based on forest type. Numéro de notice : A2004-181 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.14358/PERS.70.5.589 En ligne : https://doi.org/10.14358/PERS.70.5.589 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26708
in Photogrammetric Engineering & Remote Sensing, PERS > vol 70 n° 5 (May 2004) . - pp 589 - 604[article]Estimation of leaf water status to monitor the risk of forest fires by using remotely sensed data / M. Maki in Remote sensing of environment, vol 90 n° 4 (30/04/2004)
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Titre : Estimation of leaf water status to monitor the risk of forest fires by using remotely sensed data Type de document : Article/Communication Auteurs : M. Maki, Auteur ; M. Ishiahra, Auteur ; M. Tamura, Auteur Année de publication : 2004 Article en page(s) : pp 440 - 450 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] bande infrarouge
[Termes IGN] image SPOT-Végétation
[Termes IGN] incendie de forêt
[Termes IGN] Normalized Difference Water Index
[Termes IGN] rayonnement proche infrarouge
[Termes IGN] risque naturel
[Termes IGN] sécheresse
[Termes IGN] stress hydrique
[Termes IGN] surveillance forestièreRésumé : (Auteur) Estimating the water status of vegetation is one of the most important elements in assessing forest fire danger. In this paper, laboratory measurement confirmed a relationship between leaf water status and the normalized difference water index (NDWI), derived from nearinfrared and shortwave-infrared spectral data. Two results were confirmed: (a) NDWI is related to equivalent water thickness, and, (b) in addition to NDWI, the quantity of leaf material must be known in order to estimate vegetation dryness. Based on these findings, the authors developed a vegetation dryness index (VDI) to estimate global vegetation water content. VDI values, calculated by using SPOT/VEGETATION data, were applied to data from a 1998 forest fire in the Russian Far East. This led to two results: (a) VDI was useful for detecting areas with a high potential for ignition, and (b) VDI may have been able to detect the fire-spread direction. Numéro de notice : A2004-190 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.rse.2004.02.002 En ligne : https://doi.org/10.1016/j.rse.2004.02.002 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26717
in Remote sensing of environment > vol 90 n° 4 (30/04/2004) . - pp 440 - 450[article]Altimeter observations of sea-level variability off the west coast of North America / J.Y. Cherniawsky in International Journal of Remote Sensing IJRS, vol 25 n° 7 (April 2004)
PermalinkA comparative assessment on the use of SAR and high-resolution optical images in ocean dynamics studies / D.A. Gagliardini in International Journal of Remote Sensing IJRS, vol 25 n° 7 (April 2004)
PermalinkFour years of oceans colour remote sensing with MOS-IRS / M. Hetscher in International Journal of Remote Sensing IJRS, vol 25 n° 7 (April 2004)
PermalinkIn situ measurements of chlorophyll fluorescence and water optical properties as surface data for SeaWIFS, MODIS and MERIS / J.F.R. Gower in International Journal of Remote Sensing IJRS, vol 25 n° 7 (April 2004)
PermalinkA sea surface fractal model for ocean remote sensing / F. Berizzi in International Journal of Remote Sensing IJRS, vol 25 n° 7 (April 2004)
PermalinkSeaWIFS validation in European coastal waters using optical and bio-geochemical measurements / S.J. Lavender in International Journal of Remote Sensing IJRS, vol 25 n° 7 (April 2004)
PermalinkGlobal fire monitoring: use of MODIS near-real-time satellite data / D.J. Davies in GIM international, vol 18 n° 4 (April 2004)
PermalinkThe determination of the atmospheric optical thickness over western Europe using SeaWiFS imagery / A.A. Kokhanovsky in IEEE Transactions on geoscience and remote sensing, vol 42 n° 4 (April 2004)
PermalinkGeometric correction accuracy of IRS-1D PAN imagery using topographic map versus GPS control points / M. Turker in International Journal of Remote Sensing IJRS, vol 25 n° 6 (March 2004)
PermalinkMapping residential density patterns using multi- temporal Landsat data and decision-tree classifier / S. Mccauley in International Journal of Remote Sensing IJRS, vol 25 n° 6 (March 2004)
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