Centre de documentation
scientifique

Land degradation assessment in an African dryland context based on the Composite Land Degradation Index and mapping method / Felicia Akinyemi in Geocarto international, vol 36 n° 16 ([01/09/2021])  

Public [article]  inGeocarto international > vol 36 n° 16 [01/09/2021] . - pp 1838 - 1854 Titre : Land degradation assessment in an African dryland context based on the Composite Land Degradation Index and mapping method Type de document : Article/Communication Auteurs : Felicia Akinyemi, Auteur ; Laura T. Tlhalerwa, Auteur ; Peter N. Eze, Auteur Année de publication : 2021 Article en page(s) : pp 1838 - 1854 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Cartographie thématique [Termes IGN] Botswana [Termes IGN] carte de la végétation [Termes IGN] dégradation de l'environnement [Termes IGN] dégradation des sols [Termes IGN] données de terrain [Termes IGN] système d'information géographique [Termes IGN] utilisation du sol [Termes IGN] zone aride Résumé : (auteur) Increasing environmental and socioeconomic transformations in African drylands are driving land degradation. Using the Composite Land Degradation Index, this study assessed physical, chemical and biological degradation by determining their extent and severity. Palapye, an agro-pastoral region in eastern Botswana was used as a case study. Land degradation maps (status and indicators) were created with data from the field, soil chemical properties and image interpretation. Areas in the vicinity of settlements with Luvisols at elevations between 773 and 893 m were most degraded, implying impacts from human activities. This study developed a comprehensive list of of land degradation indicators for Botswana and created additional symbols for mapping indicators. Creation of these reference data for 2015 will facilitate the monitoring of land degradation in Palapye. The integrative and spatially explicit procedure utilized in this study can be adapted for assessing and validating local-level land degradation baseline and estimates towards operationalizing Land Degradation Neutrality in all countries. Numéro de notice : A2021-582 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10106049.2019.1678673 Date de publication en ligne : 25/10/2019 En ligne : https://doi.org/10.1080/10106049.2019.1678673 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98194 [article]

Monitoring of a laboratory-scale inland-delta formation using a structured-light system / Devrim Akca in Photogrammetric record, vol 31 n° 154 (June - August 2016)  

Public [article]  inPhotogrammetric record > vol 31 n° 154 (June - August 2016) . - pp 121 - 142 Titre : Monitoring of a laboratory-scale inland-delta formation using a structured-light system Type de document : Article/Communication Auteurs : Devrim Akca, Auteur ; Hansjörg Seybold, Auteur Année de publication : 2016 Article en page(s) : pp 121 - 142 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques [Termes IGN] analyse comparative [Termes IGN] analyse diachronique [Termes IGN] Botswana [Termes IGN] données spatiotemporelles [Termes IGN] érosion hydrique [Termes IGN] géomorphologie [Termes IGN] modèle numérique de terrain [Termes IGN] pente [Termes IGN] sédimentation [Termes IGN] surveillance géologique Résumé : (auteur) A reduced complexity model, which simulates the process of fluvial inland-delta formation, has been developed in a previous study. The results have been compared and validated with a laboratory experiment. This work elaborates the laboratory investigation in which an experimental inland delta is generated and its eroding topography is measured using a structured-light 3D scanner. The least squares 3D (LS3D) co-registration and comparison method is used for alignment as well as for comparing data epochs both spatially and temporally. A spatial precision value of around ±50 μm (1/20 000) is achieved. A series of high-quality digital elevation models (DEMs) are generated and the space-time evolution of the inland delta is monitored and analysed, in terms of slope and topography dynamics, in the consecutive DEM layers. The combination of high-resolution scanning together with high-precision co-registration techniques allows investigation of the details of the space-time variability of the sedimentation-deposition patterns to be used for geomorphological analysis. Numéro de notice : A2016-465 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1111/phor.12149 Date de publication en ligne : 17/06/2016 En ligne : https://doi.org/10.1111/phor.12149 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81470 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
106-2016021	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Employing ground and satellite-based QuickBird data and Random forest to discriminate five tree species in a Southern African Woodland / Samuel Adelabu in Geocarto international, vol 30 n° 3 - 4 (March - April 2015)  

Public [article]  inGeocarto international > vol 30 n° 3 - 4 (March - April 2015) . - pp 457 - 471 Titre : Employing ground and satellite-based QuickBird data and Random forest to discriminate five tree species in a Southern African Woodland Type de document : Article/Communication Auteurs : Samuel Adelabu, Auteur ; Timothy Dube, Auteur Année de publication : 2015 Article en page(s) : pp 457 - 471 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] Afrique du sud (état) [Termes IGN] analyse diachronique [Termes IGN] Botswana [Termes IGN] classification par forêts d'arbres décisionnels [Termes IGN] données de terrain [Termes IGN] espèce végétale [Termes IGN] forêt [Termes IGN] image hyperspectrale [Termes IGN] image Quickbird [Termes IGN] rééchantillonnage [Termes IGN] réflectance végétale [Termes IGN] savane Résumé : (Auteur) With the emergence of very high spatial and spectral resolution data set, the resolution gap that existed between remote-sensing data set and aerial photographs has decreased. The decrease in resolution gap has allowed accurate discrimination of different tree species. In this study, discrimination of indigenous tree species (n = 5) was carried out using ground based hyperspectral data resampled to QuickBird bands and the actual QuickBird imagery for the area around Palapye, Botswana. The purpose of the study was to compare the accuracies of resampled hyperspectral data (resampled to QuickBird sensors) with the actual image (QuickBird image) in discriminating between the indigenous tree species. We performed Random Forest (RF) using canopy reflectance taking from ground-based hyperspectral sensor and the reflectance delineated regions of the tree species. The overall accuracies for classifying the five tree species was 79.86 and 88.78% for both the resampled and actual image, respectively. We observed that resampled data set can be upscale to actual image with the same or even greater level of accuracy. We therefore conclude that high spectral and spatial resolution data set has substantial potential for tree species discrimination in savannah environments. Numéro de notice : A2015-306 Affiliation des auteurs : non IGN Thématique : FORET/GEOMATIQUE/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10106049.2014.885589 Date de publication en ligne : 31/03/2014 En ligne : https://doi.org/10.1080/10106049.2014.885589 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76524 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
059-2015021	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Semisupervised learning of hyperspectral data with unknown land-cover classes / G. Jun in IEEE Transactions on geoscience and remote sensing, vol 51 n° 1 Tome 1 (January 2013)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 51 n° 1 Tome 1 (January 2013) . - pp 273 - 282 Titre : Semisupervised learning of hyperspectral data with unknown land-cover classes Type de document : Article/Communication Auteurs : G. Jun, Auteur ; J. Ghosh, Auteur Année de publication : 2013 Article en page(s) : pp 273 - 282 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] analyse de groupement [Termes IGN] apprentissage semi-dirigé [Termes IGN] Botswana [Termes IGN] classification bayesienne [Termes IGN] image hyperspectrale [Termes IGN] occupation du sol [Termes IGN] régression [Termes IGN] réponse spectrale [Termes IGN] variation Résumé : (Auteur) Both supervised and semisupervised algorithms for hyperspectral data analysis typically assume that all unlabeled data belong to the same set of land-cover classes that is represented by labeled data. This is not true in general, however, since there may be new classes in the unexplored regions within an image or in areas that are geographically near but topographically distinct. This problem is more likely to occur when one attempts to build classifiers that cover wider areas; such classifiers also need to address spatial variations in acquired spectral signatures if they are to be accurate and robust. This paper presents a semisupervised spatially adaptive mixture model (SESSAMM) to identify land covers from hyperspectral images in the presence of previously unknown land-cover classes and spatial variation of spectral responses. SESSAMM uses a nonparametric Bayesian framework to apply spatially adaptive mechanisms to the mixture model with (potentially) infinitely many components. In this method, each component in the mixture has spatially adapted parameters estimated by Gaussian process regression, and spatial correlations between indicator variables are also considered. The proposed SESSAMM algorithm is applied to hyperspectral data from Botswana and from the DC Mall, where some classes are present only in the unlabeled data. SESSAMM successfully differentiates unlabeled instances of previously known classes from unknown classes and provides better results than the standard Dirichlet process mixture model and other alternatives. Numéro de notice : A2013-014 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2012.2198654 En ligne : https://doi.org/10.1109/TGRS.2012.2198654 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32152 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
065-2013011A	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Disturbance, management, and landscape dynamics: harmonic regression of Vegetation Indices in the Lower Okavango Delta, Botswana / A.L. Neunschwander in Photogrammetric Engineering & Remote Sensing, PERS, vol 74 n° 6 (June 2008)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 74 n° 6 (June 2008) . - pp 753 - 764 Titre : Disturbance, management, and landscape dynamics: harmonic regression of Vegetation Indices in the Lower Okavango Delta, Botswana Type de document : Article/Communication Auteurs : A.L. Neunschwander, Auteur ; K.A. Crews, Auteur Année de publication : 2008 Article en page(s) : pp 753 - 764 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] analyse diachronique [Termes IGN] analyse harmonique [Termes IGN] Botswana [Termes IGN] delta [Termes IGN] image Landsat-ETM+ [Termes IGN] image Landsat-TM [Termes IGN] indice de végétation [Termes IGN] plan d'occupation du sol [Termes IGN] régression [Termes IGN] série temporelle [Termes IGN] surface cultivée [Termes IGN] traitement du signal Résumé : (Auteur) Focused on the Okavango Delta, Botswana, this research investigates (a) whether ecosystem signals derived from remotely sensed imagery can be decomposed using a harmonic regression, (b) if the deviations from the decomposed signal are correlated with observed flooding and fire regimes, and (c) the impact of explicitly including agriculture, settlement areas, and land management systems on the derived signals. A time-series of 85 TM/ETM+ scenes spanning the period from 1989 through 2002 was used to decompose derived landscape dynamics into trends, annual and seasonal cycles, and long term oscillations. The harmonic fit largely defined by climatic periodicities (semi-annual, annual, and quasi-decadal) accounted for 63 percent to 88 percent of the variance in the trajectories. The trends were found to be robust whether or not urban settlement or landscape management regimes were explicitly included, though there was a reversal of trend in agricultural areas. Copyright ASPRS Numéro de notice : A2008-200 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.74.6.753 En ligne : https://doi.org/10.14358/PERS.74.6.753 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29195 [article]

Proposed methodology for georeferencing and mosaicking Corona photographs / H. Hamandawana in International Journal of Remote Sensing IJRS, vol 28 n° 1-2 (January 2007)  

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Result from EO-1 experiment: a comparative study of earth observing-1 Advanced Land Imager (ALI) and Landsat ETM+ data for land cover mapping in the Okavango delta, Botswana / A.L. Neunschwander in International Journal of Remote Sensing IJRS, vol 26 n° 19 (October 2005)  

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The development and causes of range degradation features in southeast Botswana using multi-temporal Landsat MSS imagery / S. Ringrose in Photogrammetric Engineering & Remote Sensing, PERS, vol 56 n° 9 (september 1990)  

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Spatial variation in elephant impact on the Zambezi teak forest in the Chobe national park, Botswana / M.D. Nellis in Geocarto international, vol 5 n° 2 (June - August 1990)  

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The darkening effect in drought affected savanna woodland environments relative to soil reflectance in Landsat and Spot wavebands / S. Ringrose in Remote sensing of environment, vol 30 n° 1 (01/10/1989)  

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Reflectance characteristics and surface processes in stabilized dune environments / P.A. Jacobberger in Remote sensing of environment, vol 28 n° 1 (April - June 1989)  

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Differentiation of ecological zones in the Okavango delta, Botswana by classification and contextural analyses of Landsat MSS data / S. Ringrose in Photogrammetric Engineering & Remote Sensing, PERS, vol 54 n° 5 (may 1988)  

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Spectral assessment of indicators of range degradation / S. Ringrose in Remote sensing of environment, vol 23 n° 2 (01/11/1987)  

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