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Mapping and monitoring agricultural land use in West Africa
Abstract/Description
West Africa has experienced increases in cultivated lands over the last 50 years in order to meet increasing demand from rapidly growing populations. Most countries in the region still depend on agriculture as an important part of the economy. In most countries however agricultural productivity is low leading to food insecurity and poor performance of the whole sector. In the Maputo declaration of 2004 the African governments committed to spending at least 10% of the national budget resources on a process of revitalizing the agricultural sector. For proper planning and investment strategies as well as policies to direct these for different crops, cropping systems and agricultural markets recent landuselandcover maps are necessary. Currently the most recent landcover set available is GLC2000 with 1 km resolution. The present work is therefore exploring the use of free available current images at higher resolutions to provide recent landuse maps for the ECOWAS countries of West Africa. 8-day composites of 500m resolution Moderate Resolution Imaging Spectroradiometer (MODIS) imagery of the year 2006 were used to produce a land cover map of West Africa. The percentage of cropland in each land cover classes were estimated with the combination of high resolution images (LANDSAT ETM 7), and very high resolution images (Quickbird and IKONOS acquired between 2000 and 2007 for several sites in West Africa as well as high resolution images digitized from Google earth). The preliminary results show different proportions of croplands in the different landcover classes. For instance, closed deciduous woodland of the coastal region of West Africa has between 10-15% cultivated land while 20-35% of croplands were found in the savanna shrubland. The approach demonstrates a simple and cost effective way of mapping croplands using MODIS data.