This function calculates radiance
calcRadiance(image.DN, sat = "auto", MTL)raw image in digital numbers
"L7" for Landsat 7, "L8" for Landsat 8 or "auto" to guess from filenames
Landsat Metadata File
R. G. Allen, M. Tasumi, and R. Trezza, "Satellite-based energy balance for mapping evapotranspiration with internalized calibration (METRIC) - Model" Journal of Irrigation and Drainage Engineering, vol. 133, p. 380, 2007 LPSO. (2004). Landsat 7 science data users handbook, Landsat Project Science Office, NASA Goddard Space Flight Center, Greenbelt, Md., (http://landsathandbook.gsfc.nasa.gov/) (Feb. 5, 2007)
Other remote sensing support functions: calcSR,
calcTOAr, cfmask,
loadImageSR, loadImage