The development of airborne and satellite multi-spectral scanning radiometers has created widespread interest in the application of such sensors to mapping of earth resources. The energy sensed in each band can be used as a parameter in a computer-based, multidimensional-pattern-recognition process to aid in the interpretation of the nature of elements in the scene. Images from each band can also be interpreted visually. Visual interpretation of 5 or 10 multispectral images simultaneously becomes impractical, especially as the area studied increases; hence, great emphasis has been placed on machine (computer-assisted) techniques in the interpretation process.A number of other data sets have recently been studied and integrated by digital registration with the multispectral reflectance and radiance phenomena. Topographic data, which have been registered with four-band Landsat multispectral scanner (MSS) data, are being studied to determine relationships between spectral and topographic variables. Geophysical variables, including gamma-ray and magnetic data, have also been registered and studied using the multivariate analysis approach.