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Accueil du site → Doctorat → Allemagne → Methodologische Untersuchungen zur Veränderung sahelischer Überschwemmungsgebiete mittels Fernerkundung : Fallbeispiel Nigerbinnendelta (Mali)

Universität Mainz (2003)

Methodologische Untersuchungen zur Veränderung sahelischer Überschwemmungsgebiete mittels Fernerkundung : Fallbeispiel Nigerbinnendelta (Mali)

Hess Sigrid

Titre : Methodologische Untersuchungen zur Veränderung sahelischer Überschwemmungsgebiete mittels Fernerkundung : Fallbeispiel Nigerbinnendelta (Mali)

Auteur : Sigrid Hess

Université de soutenance : Universität Mainz

Grade : Doktorgrade 2003

Résumé
Long-time monitoring of landscape dynamics in Sahelcountries are confronted to a lack of quantitative spatialinformation in general. This lack of local to regional leveldata has induced to a methodological study, dealing with thedevelopment of methods for acquisition and analysis ofmulti-temporal data to landscape changes. Historical remotesensing data are covering with huge sheets the region ofWestafrica. There are high resolution aerial photographsfrom up to the 50ies so as some first earth observationsatellite data of Landsat MSS from up to the 70ies. Multitemporal long-time monitoring requires respective toditital data reproductivity, data comparability and objectextraction the a-priori consideration of data property andquality. Two methods, developed without available, nor reproduciblesoil control data are showing not only the potential, butalso the limits of radiometric and morphometric informationgain of image data. Within the favoured inonndation area ofthe Internal Niger Delta of central Mali two partial studiesare treating the radiometric and atmospheric problemsrelated to the extraction of quantitative data of Sahelianwood objects : 1. Preprocessing homogenization of multitemporal MSSarchive data with simulations of the impact of atmosphericand sensor-induced effects 2. Development of a method to semi-automatic recognitionand quantification of dynamics of wood cover density onpanchromatic historical aerial photographs The first partial study exposes Landsat MSS historicalsatellite data as unsuitable for multi-temporal analyses oflandscape dynamis. The second partial study presents thedevelopment of a special method to automated wood coverrecognition and quantification by the use ofmorpho-mathematic filter operations. Finally, the postulation of cost- and time efficient methodstandards is discussed in view of a representativity tolong-time monitoring of reource inventories in semi-aridregions, so as of the operational transferability betweenhistorical remote sensing data and such data of modernsensors

Mots clés : Niger ; Überschwemmungsgebiet ; Vegetation sentwicklung ; Fernerkundung ; Mali

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