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The greatest disadvantage in the use of infrared and other non-photo 
graphic sensors is the high cost involved in obtaining imagery. Scanner cover 
age must generally be obtained in addition to aerial photography, and interpre 
tation can be severely hampered when the two types of imagery differ appreciably 
in terms of scale, date, or season. In brief, there is a bright future for 
non-photographic sensors in aerial archeology, but conventional aerial photo 
graphs will continue to be preferred for single-coverage and reconnaissance 
flights.* 
*This paper represents part of a new chapter in the author’s forthcoming third 
edition of Interpretation of Aerial Photographs (Burgess Publishing Company, 
Minneapolis, Minnesota, USA). All rights reserved.