Modelling and Simulation Conference, December 2013 Assessment of Spatial Models using Ground Point Data: Soil Matrix and Radiometric Approach S.J. Hill a , G.R. Hancock a and G.R Willgoose b a School of Environmental and Life Science, University of Newcastle, Callaghan, New South Wales, Australia b School of Engineering, University of Newcastle, Callaghan, New South Wales, Australia Email: s.j.hill@uon.edu.au Abstract: In this paper we present an assessment of the national airborne radiometrics model (NARM) using point based field data (soil samples) using landscape properties of topography, soils and geology. The Krui catchment, in north-west of the Hunter Valley NSW, Australia was used as the study site. Soils were sampled across two scales, and 40 K concentration of the soil samples determined. Relationships between the field 40 K and NARM 40 K were investigated using a digital elevation model, the national soil atlas model and the national geology model. Our results showed that the NARM and field data are correlated and that this correlation extends across changing soil types and geology. A complex relationship with topographical features was also determined which needs further investigation. Keywords: Radiometric model, field testing, model assessment, potassium, soils