Early aerial thermal infrared images from Yellowstone National Park

Top: the first thermal infrared images of Yellowstone (1961).  Warm areas are brighter; cold areas are darker.  These images were published in: McLerran, J.H. and Morgan, J.O. (1965) Thermal mapping of Yellowstone National Park. Proceedings of the 3rd International Symposium on Remote Sensing of Environment, University of Michigan, Institute of Science and Technology, Ann Arbor, MI, pp. 517-530. Bottom: the first thermographic mosaic of Yellowstone (April 1969).  These image strips were acquired by flying an infrared line scanner that was modified for video tape recording along dozens of adjacent flight lines.  This type of airborne image acquisition resulted in many distortions and striping effects due to differing look angles.  Some of these artifacts could be corrected in image post-processing.  This uncontrolled mosaic was published in: Williams Jr, R.S., Hasell Jr, P.G., Sellman, A.N. and Smedes, H.W. (1976). Thermographic mosaic of Yellowstone National Park. Photogrammetric Engineering and Remote Sensing, 42(10), pp.1315-1324.