APPLICATION OF REMOTE SENSING AND GIS IN MONITORING AND MAPPING OF SAND ENCROACHMENT IN WHITE NILE STATE, SUDAN

摘要

Sand encroachment in the White Nile State has been recognized as the serious environmental problem facing the study area, The objective of this study is to monitor and map the encroachment of sand dunes, using remotely sensed imagery and GIS techniques for the period 1974-2008 and moreover to evaluate the efficiency of remote sensing, GIS and GPS in achieving this objective. For this purpose four satellite images (MSS 1974, TM 1986, ETM+ 2000 and 2008) were used, in addition to field survey for ground control point collection. Visual interpretation, supervised classification and change detection were applied. The result of the study revealed that the shifting dunes during 1974-2008 increased while the fixed dunes decreased by an annual rate of 0.31% and 0.44%, respectively. The vegetation cover (dense vegetation + pasture land) in the study area has decreased by an annual rate of 0.48%.