Air Photo Interpretation Procedures # t 
kirk h. stone, Professor of Geography, 
University of Wisconsin, 
Madison, Wis.% 
\IR photo interpretation is a way of using research material. The technique 
is valuable in research primarily as procedure when air photos are employed 
with other source materials. Yet, study of the literature of air photo interpreta 
tion reveals a serious absence of procedures. 1 Numerous references are available 
on the photographic characteristics of features, that is, on the recognition of 
objects or the clues to what is seen. However, there are few publications on how 
to interpret—the very heart of the technique—and air photo interpretation 
has remained unnecessarily mystical as a result. 
Some standardization of interpretational procedures is possible in spite of 
the variety of objectives of research involving air photos. Thus, suggestions for 
standardization are made in this paper in order to aid beginning interpreters, 
to provoke study and extension by those more experienced, and to remind all 
researchers of the value of publishing procedures of study with the final results. 
The recommendations are made with the assumption that source materials are 
used with the photographs but that sources are somewhat limited and, therefore, 
that some general questions can be answered only by analysis of the air photos. 
It is further assumed that once the interpreter has employed the procedures 
and has noted differences between elements of the photographed landscape he 
will proceed with the explanation of these differences, a stage more dependent 
upon knowledge of the content of a field of study rather than upon a technique. 
The foundation of procedure is mental discipline. So it is in air photo inter 
pretation that the primary tools are the brain and at least one eye. Other 
equipment is secondary. However, the need for mental discipline often is over 
looked because of the adjustments necessary to the unfamiliar viewpoints of 
the oblique and vertical photos, of the apparent desirability of much of the 
“photo interpretation equipment” available, and of an unconscious desire to 
learn about everything in a landscape because part of the great mixture seen 
on mosaics or photos is recognizable immediately. Thus, the hardest part of air 
photo interpretation is getting started efficiently, a step based on four general 
procedures. 
General Procedures 
1) Interpretation should he done in a methodical way. An air photo is a record 
of the natural mixture of the physical and cultural elements of a landscape. To 
prevent initial confusion and discouragement by this mixture, and to insure 
completeness of analysis, nine basic steps of interpretation have been suggested 
previously. 2 They have proved to be useful in geographic research and teaching. 
Especially valuable in preventing confusion is the technique of interpreting only 
* A contribution of Commission VII, Photographic Interpretation, International Society of 
Photogrammetry. 
f Based on research and teaching supported by the University of Wisconsin. 
X On leave 1955-56 as Fulbright Research Scholar at the University of Oslo, Oslo, Norway. 
1 Stone, K. H., “A Selected Bibliography for Geographic Instruction and Research by Air 
Photo Interpretation,” Photogrammetric Engineering, v. XX, 1954, p. 561-565. 
2 Stone, K. H., “Aerial Photographic Interpretation of Natural Vegetation in the Anchorage 
Area, Alaska,” Geographical Review, v. XXXVIII, 1948, p. 466.