SLC CONCEPTS AND DEFINITIONS

The framework for the thematic map definition was established using the following concepts and definitions:

• Map polygons are the smallest delineated spatial element. Each polygon consists of one or more soil landscape components.
• The full array of polygon attributes that describe a distinct type of soil and its associated landscape attributes, such as surface form, slope, watertable depth, permafrost and lakes, is called a soil landscape.
• A polygon may contain one or more distinct soil landscape components (dominant or subdominant) and may also contain small but highly contrasting inclusion components. The location of these components within the polygon is not defined.
• The dominant (or most prominent) soil landscape component represents at least 40% of the land area within the polygon whereas the subdominant soil landscape component represents between 16 to <40% of the land are within the polygon; inclusion components represent <16% of the land area within the polygon.
• Each polygon is assigned a unique identifying number.
• The attributes separating one polygon from another include:
  1. ecoclimatic region;
  2. soil development;
  3. soil parent material mode of deposition;
  4. texture class of parent material;
  5. local surface form;
  6. slope gradient class (in percent);
  7. kind of rock or surface material (except water); and
  8. spatial occurrence of these attributes within a polygon.
  These attributes may apply to either the dominant or subdominant soil landscape component. Attributes (b) to (f) were included in the printed map symbol.
• The size of the map polygon should not be less than 1 x 1 cm at the 1:1 million scale (100 km2), although smaller, isolated areas are permitted when necessary.

Source: Shields et al., 1991
Contact: Peter Schut