cameras. If we realize further that tonal rendition in aerial photographs is
influenced by many other factors such as film processing, atmospheric factors,
etc., it appears that the knowledge of absolute reflectance values may not be
a very significant type of information to have. Considering the great complex
ity of the system I am inclined to favour the posteriori approach to photo
analysis at this time, i.e. working from "what we have" rather than from
"what we should have". This is not to say that we should not go on with the
investigation and study of the reflectance phenomenon. Apart from the appli
cation that knowledge of reflected energy may or may not have in remote
sensing, its relation to absorptance makes it a very useful quantity in energy
budget studies of vegetation.
ACKNOWLEDGEMENT
The above work was financed and assisted in other material and
intangible ways by the Forest Management Institute, Department of the
Environment, Ottawa.