Desertification is a serious threat to human survival and to ecosystems, especially to inland
desert oases. An assessment of desertification severity is essential to ensure national sustainable
development for agricultural and land expansion processes in this region. In this study, Index
of Land Susceptibility to Wind Erosion (ILSWE) was integrated with a Modified Mediterranean
Desertification and Land Use (MEDALUS) method and factor analysis (FA) to develop a GIS-based
model for mapping desertification severity. The model was then applied to 987.77 km2 in the El-
Farafra Oasis, located in the Western Desert of Egypt, as a case study. Climate and field survey
data together with remote sensing images were used to generate five quality indices (soil, climate,
vegetation, land management and wind erosion). Based on the FA, a weighted value was assigned to
each index. Five thematic layers representing the indices were created within the GIS environment
and overlaid using the weighted sum model. The developed model showed that 59% of the total
area was identified as high-critical and 38% as medium-critical. The results of an environmentally
sensitive area index suggested by the original MEDALUS model indicated similar results: 18.37% of
the total area was classified as high-critical and 78.73% as medium-critical. However, the sensitivity
analysis indicated that weights derived from FA resulted in better performance of the developed
spatial model than that derived from the original MEDALUS method. The proposed model would
be a suitable tool for monitoring vulnerable zones, and could be a starting point for sustainable
agricultural development in inland oases.