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REPORT OF COMMISSION VII 19
contributing to the texture of the field in which the orchard has been planted.
In practice a geometric progression of photographic scales would probably be
preferable to the arithmetic progression here shown in order to provide the same
proportionate change throughout the series. Furthermore, it should be recog-
nized that two objects or areas having the same coarseness of texture may have
somewhat different appearances because of differences in the pattern and shape
of the individual components contributing to texture. Accordingly it might be
necessary to construct several different texture scales for use by the photo-
interpreter.
(5) Pattern Scales. Pattern refers to the spatial arrangements of objects.
The repetition of certain general forms or relationships is characteristic of many
objects, both natural (Figure 15) and man-made, and gives them a pattern which
aids the photo-interpreter in recognizing them (Parvis, 1950).
E LY
WNL AA
DENDRITIC TRELLIS RADIAL PARALLEL ANNULAR
ZEN
RETICULAR ==)
FrG. 15. À portion of a “Pattern Scale,” of possible use in determining or describing the drain-
age pattern exhibited in various areas as seen on vertical aerial photographs. (Courtesy of Merle
Parvis, Joint Highway Research Project, Purdue University.)
RECTANGULAR CENTRIPETAL DICHOTOMIC BRAIDED
(6) Shape Scales. Shape relates to the general form, outline or configuration
of an object. Despite the extreme importance of shape in the recognition of
objects from their photographic images, little has been done to standardize
terminology relating to the shape of objects. In this instance, as in many others,
the interpreter does well to consider borrowing from the experience of workers
in other scientific fields. Upon so doing he finds that mathematicians, engineers,
biologists and others have developed a quite rigorous terminology for defining
the shapes of objects.
Several of these scientific terms probably should not be employed in photo-
interpretation keys either because they are unnecessarily difficult to spell,
pronounce and understand when compared with corresponding terms used by
the layman, or because they are so rarely applicable in the field of photo-
interpretation. (e.g. hippocrateriform, meaning “horse-shoe-shaped”; fundibuli-
form, meaning ‘‘funnel-shaped’’; papilionaceous, meaning ‘‘butterfly-shaped’;
pandurate, meaning ''fiddle-shaped," etc.). However, several of the scientific
terms denoting shape exhibit a very happy combination of desirable features
from the photo-interpreter's standpoint in that (1) they are easily spelled,
pronounced and understood and can therefore be used in non-technical keys
as well as in technical ones, (2) they are more precise in their meaning than
corresponding terms used by the layman, in many cases being mathematically
defined, and (3) they are applicable to a great many objects which the photo-
