Representing soil attributes in form of a continuous spatial layer is not quite the trivial task it may at first appear due to the variability of the distribution of soil properties but also the methods used to store the information. In a generalization of the methods used to map soil properties one can distinguish three main approaches:
- delineation of areas with largely common assortment of properties;
- interpolation of a surface from soil survey data;
- analysis of surface topography and catena.
A soil database with a common assortment of soil properties does not necessarily signify a homogeneous distribution of a single property across the area. Rather, it refers to a distinct diffusion of typical soil properties within the area of limited extent. The soil properties of an area are defined by a combination of several exemplified soil characteristics. As a consequence, more than one attribute is assigned to the same spatial unit which makes representing the attributes in a single layer a more complex task. For mapping soil properties from point data geo-statistical methods are widely used (Loda, et al., 2008). Depending on the method used ancillary data to support the interpolation process may be incorporated. The analysis of topographical conditions and the use of the catena concept are also referred to as “digital soil mapping” (Carré, et al, 2007). The method relies on defining functional links between the position of a soil in the landscape and typical properties associated with those positions.
In this study we use a soil database where the soil properties are stored in tables of generalized combinations of attributes and linked to a spatial layer of delineated mapping units with the aim to investigate
- the potential of providing a measure of spatial positioning of attributes of a 1-to-many link within spatial mapping units and
options of mapping all attributes associated with the mapping unit to a raster layer.
The methods should result in a set of spatial data of soil properties, which avoid the potential bias in the representation of a soil properties when mapping only the characteristics of the dominant typological unit.