Cartographie par télédétection des changements de l'occupation du sol à partir des images Landsat dans une zone d'orpaillage, département de Dimbokro (Centre-Est, Côte d'Ivoire)

Located in central-eastern Côte d'Ivoire, the department of Dimbokro has for the past ten years been faced with the illegal and clandestine development of artisanal and small-scale gold mining (ASGM), commonly known as gold panning. This activity is having a huge impact on the environment and especially on natural resources (deforestation, loss of arable land). The aim of this study is to detect changes in land cover in the Dimbokro department using Landsat TM (1988), ETM+ (2002) and OLI (2021) images. The supervised or directed classification method with maximum likelihood and the diachronic comparison method were used. The areas of the classes obtained after the diachronic analyses were used to highlight the average annual rates of spatial expansion. This expansion between 1988 and 2021 is either progressive or regressive. A regression was observed for the dense forest (-2.99%), degraded forest (-2.32%), crop (-0.82%) and water (-1.65%) classes. In terms of change over this period (33 years), there has been an increase in the surface area of savannah (+2.67%) and buildings/bare ground (+4.12%). This study shows that changes in the landscape of the Dimbokro department are linked to a high level of human activity, leading to the degradation of natural resources in a context of climatic variability.