Component Table (CMP)




The Component Table identifies the soils which are components of a Soil Map Unit.


Contents of dataset: dss_v2_REGION_cmp
Field Name Type Width Description
1 MAPUNIT string 68 Map Unit Identifier
2 CMP integer 2 Component Number
3 PERCENT integer 3 Percent of polygon occupied by the component
4 SLOPE float 5 Slope Steepness
5 STONINESS string 1 Surface Stoniness Class
6 SOILTYPE string 9 Soil Name Identifier
7 ROCKINESS string 1 Rockiness Class (optional)


  • A record in this file is unique with respect to  MAPUNIT  & CMP.
  • MAPUNIT is required to relate (1:N) to the PAT.
  • SOILTYPE is required to relate (1:N) to the NAME and LAYER tables.  Without changes to the last character of the SOILTYPE field, linkages to the NAME and LAYER tables will follow the assumption that land use is agricultural.  For more information, see the documentation for the LU_FLAG field in the NAME table.
  • Attributes which apply to the entire Soil Map Unit are found in the Map Unit Table


The proportion of the Soil Map Unit occupied by each separate component is identified. However, their location within the Soil Map Unit is not defined. While the data model does not restrict the number of components or the proportion of the Soil Map Unit that they occupy, restrictions have been recommended from a subject matter/organization standpoint.

Note that the dominant component for some Soil Map Units will be a non-soil (i.e. water, ice or rock). Analyses involving dominant soil components should take this fact into account.


Soil Map Unit Tables were created starting in 1998 from information in the original SMUF files.

The CMP number was mapped directly from the number following items of the same name in the original SMUF structure (i.e. SOIL_CODE1 became CMP #1).