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Accueil du site → Doctorat → Royaume-Uni → 1994 → The evaluation of satellite imagery in a geographic information system (GIS) for monitoring land cover changes in a semi-arid area of north-eastern Nigeria

Cranfield University (1994)

The evaluation of satellite imagery in a geographic information system (GIS) for monitoring land cover changes in a semi-arid area of north-eastern Nigeria

Abdalla, Jacob Dzarma

Titre : The evaluation of satellite imagery in a geographic information system (GIS) for monitoring land cover changes in a semi-arid area of north-eastern Nigeria

Auteur : Abdalla, Jacob Dzarma.

Université de soutenance : Cranfield University

Grade : Doctor of Philosophy (Ph.D.) : 1994

Résumé
The change over time in land cover in the fadama areas of North-East Nigeria is an important issue due to the need to plan for future agricultural and pastoral development. Landsat MSS images provide a 20-year record data set which requires analysis based on sound ground data and an appropriate classification scheme. A field survey was carried out in 1991-92 for a study area based on the Yobe floodplain. Aerial photographs of 1969 were also interpreted for the same area. The resulting data were used for the development of a functional classification scheme, as basic input for analysis of Landsat MSS imagery, and for estimation and change detection of areas of land cover types for the periods between the early 1970s and late 1980s. The resulting data were also used for the estimation and change analysis of fadama and non-fadama areas for the same period.The overall classification accuracies (75%-79%) for the satellite images prevent the resulting 12 class maps from being useful in the field except the estimated land cover areas. The satellite imagery is therefore used in combination with the ground data to produce area estimates of each of the land cover classes and two class thematic maps describing the extent of the fadama. The results show significant changes in land cover areas during the 20-year period, but the overall balance suggests the fadama is decreasing overall. The results also suggest a definite shrink in areal extent of the fadama from the outer margins inward.

Présentation : EThOS (UK)

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