Natural resource assessment at regional scales is often time consuming, expensive and reliant upon the local knowledge and judgment of the surveyor. In this chapter we describe the development of an efficient method to assess land degradation (specifically waterlogging and saline and acid soils) at a regional scale. We developed spatial models by integrating knowledge of landscape processes with remotely sensed, terrain and field data, within a geographic information system (GIS). The key to this approach was the linkage of soil and hydrological processes (identified at the point scale) to mapped soil units via toposequences, and the allocation of land degradation classes to each of the units. The data were aggregated to catchment and regional scale to produce maps of land degradation. The results obtained from the modelling were validated by random ground assessments of sites across the region. The method described here could be applied to the assessment of other types of land degradation, and to other regions with comparable landscapes and vegetative covers, where similar soils, terrain and remotely sensed data exist.