Technical Abstract: Most Geographic Information System software includes routines for atmospheric and topograhic correction of satellite imagery such as that taken by Landsat. Radiometric correction is an active area of research, and new, improved methods are rarely if ever available for testing and application. The R statistical package has excellent capabilities for prototyping, testing, and automating these algorithms for processing satellite imagery. A series of image-based absolute radiometric corrections, relative corrections, and image-processing utilities have been implemented in R. These tools are being used for research and development of satellite-based monitoring capabilities in agricultural grasslands.