ETM+ and OLI image TOA reflectance over the ROI were calculated using the Landsat Image Assessment (IAS) PICS database. EO-1 Hyperion images were available in the USGS EarthExplorer database. It should be noted that historically Landsat calibration has been always based on the MODerate resolution atmospheric TRANsmission (MODTRAN) based ChKur solar model [25]. Hence for consistency, the same ChKur model is used for converting at-sensor radiance to TOA reflectance for both the ETM+ and the Hyperion sensors.