Map Unit Composition Assessment Using Drainage Classes Defined by Landsat Data

Abstract

AbstractSoil survey map units are designed such that the dominant soil represents the major proportion of the unit. At times, soil mapping delineations do not adequately represent conditions as stated in the map unit descriptions. Digital analysis of Landsat multispectral scanner (MSS) data provides a means of accurately delineating and quantifying soil map unit composition.Digital analysis of Landsat MSS data collected on 9 June 1973 was used to prepare a spectral map for a 430‐ha area in Clinton County, Indiana. Sixteen spectral classes were defined, representing 12 soil and 4 vegetation classes. The 12 spectral soil classes correlated with soil drainage characteristics and were grouped into four drainage classes. The four spectral vegetation classes were grouped for convenience into one vegetation class.The soil delineations produced using these groupings were compared to a conventionally prepared soil map. Three map units were investigated in detail: (i) Mahalasville silty clay loam, poorly drained; (ii) Reesville silt loam, 0 to 2% slopes, somewhat poorly drained; and (iii) Xenia silt loam, 2 to 6% slopes, eroded, moderately well drained.Results indicate that soil drainage characteristics can be identified. Correlation of drainage characteristics with soil series allows for the composition of soil map units to be accurately ascertained.