S-map – a new soil database for New Zealand

Soil information in New Zealand comprises maps and databases of varying accuracy and platforms. A project has been initiated to bring together this soil information in S-map – a new multi-layer soil database with national coverage. An important difference is that S-map is designed as a digital product and is thus not constrained by cartographic requirements. Rather than generalising polygons for aesthetic reasons, the best available information is now used regardless of its scale of origin. Also climate and topography are no longer used as soil descriptors. Key goals are to capture the fundamental soil inputs required by pedotransfer functions, and to record knowledge of uncertainty. This will then act as a platform for fusion with other environmental layers for spatial modelling. \nS-map will contain data predominantly new to the existing national spatial soil database. Gaps will be filled and previous low-resolution data will be upgraded. The aim is to provide digital data layers of soil classes and attributes with resolution at least equivalent to 1:50 000. Work in the lowlands is proceeding using conventional soil survey techniques. In the uplands (where relief is sufficient to make effective use of the national 25-m resolution DEM) modelling approaches are used with the technique depending on data type and terrain. \nThere are some enormous challenges in this work including nationwide soil correlation, devising a common structure for lowland (good information) and upland (little information) soils, providing information about soil variability and uncertainty, and developing a model-base of pedotransfer functions that can be easily updated. This paper describes our approach and progress in solving these challenges. \n