There are basically two levels of calibrations and validation of digitally acquired spectral and other information via sensors carried on space-borne or airborne platforms. The basic level is carried out by the data producers executed by comparison made of results taken over test fields for example. The second level. more a part of a supervised classification effort are carried by the... https://www.roneverhart.com/Carhartt-Sherpa-Lined-Mock-Neck-Vest/