Locating boundaries between mapping units

  • James B. Campbell


A linear discriminant function can be used to place the boundary between two mapping units, if multiple measurements are available for samples collected from both units. The function is calculated using samples of known group membership, then is applied to classify samples of unknown group identity. The plot of the discriminant index on a map of the study area locates the contact between the two groups. Boundary position can be evaluated by comparing data models based upon the boundary with the distributions of the original variables. This method is applied to locate the boundary between two soil mapping units. Samples of two contrasting soils were collected on a gridded sampling pattern positioned at the contact between two mapping units. Samples were analyzed for physical and chemical properties, including sand content, silt content, and pH. The boundary was located, then separately evaluated with respect to the sand, silt, and pH measurements. The discriminant score boundary corresponded closely to the sand content measurements, but did not match the silt or pH distributions.

Key words

classification discriminant analysis soil science autocorrelation boundary 


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Copyright information

© Plenum Publishing Corporation 1978

Authors and Affiliations

  • James B. Campbell
    • 1
  1. 1.Department of GeographyVirginia Polytechnic Institute and State UniversityBlacksburg

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