RFMOTE SENSINC OF ENVIRONMENT 17:301-306 (1985) SHORT COMMUNICATION A TM Tasseled Cap Equivalent Transformation for Reflectance Factor Data*

The Tasseled Cap transformations of Landsat MSS (Kauth and Thomas, 1976) and TM (Crist and Cicone, 1984a,b) data provided a mechanism for data volume reduction and enhanced data interpretability by emphasizing the structures in the spectral data which arise as a result of particular physical characteristics of scene classes. The basic concepts underlying these transformations are discussed by Crist and Kauth (1985). Because the expression of the data structures is influenced by sensor calibration and detector response, the transformations are sensordependent: i.e., the transformation matrix for MSS data cannot be applied successfully to TM data. Similarly, the transformation matrix for actual TM signal count data cannot be directly applied to reflectance factor data, even if those reflectance factor data are collected or combined in bands equivalent to those of the TM. Scientific investigations related to the use of satellite remotely sensed data for monitoring vegetation often include use of ground level (truck-mounted or handheld) spectrometer data to supplement data from the spaceborne sensor. Such data can be collected under more controlled conditions, allowing detailed analysis of the physical characteristics of the entities being observed as well as their spectral response. This paper presents a transformation by which one type of reflectance factor data may be converted to TM Tasseled Cap equivalent features. Others have used a "TasseledCaplike" approach to defining dataset-specific transformations for reflectance data (e.g., Jackson, 1983). Some of the differences between such approaches and the Tasseled Cap transformations of MSS and TM data are discussed specifically by Crist and Cicone (1984b) and can be inferred from Crist and Kauth (1985). The transformation presented here i s intended to provide features which relate as directly as possible %is work was supparted by the Earth Sciences and to the corresponding TM Tasseled Cap Applications Division of the NASA Johnson Space Center under Contract NASS-16538. ERlM Paper 16D3M91-J. features. Such a direct relationship allows