Digital mapping is a key tool to study, understand and depict environmental parameters. Spatial variability within the landscape is measured at point observation locations, and it is modelled as continua using spatially exhaustive ancillary information. Many technologies are available as sources of usable and low cost ancillary information, such as probe sensing (e.g. proximal geophysics, air borne laser scanning, satellite imagery), and digital terrain analysis (e.g. combining a digital elevation model with the gravitational field). The complete picture of the environmental complexity is...