Role of remote sensing in the analysis of bare soil in a Sudanian Savanna (Burkina Faso)

High-resolution SPOT (System Probatoire pour l'Observation de la Terre) sat ellite imagery was used to detect patches of bare soil in a Sudanian savann ah zone. The objectives of this work were linked to hydrology, i.e. towards a better understanding of the runoff generation in small catchments due to the presence and distribution on these surfaces. The mapping accuracy was estimated using very fine ground documents as reference (scale 1/10 000), b y comparing the distribution of patch number, area and shape. The mapping q uality was determined through a separation in geometric errors due to resol ution (scale effects) and radiometric errors due to bands and date of the i mage. In respect of the thematic objectives, the determination appears accu rate (the smallest well detected patches were 0.25 ha in area) using a wet season image (great contrast between bare soils and cultivated areas). The study area was a small area of Burkina Faso (imige catchment area of 12 km( 2)).