The use of air photographs as an aid to understanding and mapping
natural resources has long been an established technique. The advent of
satellite imagery was, and indeed by many still is, regarded as a very
high altitude air photograph, but with the introduction of digital
techniques the full analysis of imagery has become very sophisticated.
Radar imagery presents the resource scientist with a new imaging
technique that has to be understood and used, a technique which,
although in many respects still in its infancy, has considerable
applications potential for resources studies. Remote sensing now forms
an element in study courses in the earth sciences in many major
universities and a number of universities offer specialist post-graduate
courses in remote sensing. Nevertheless there are a large number of
earth scientists already working with imagery who have progressed from
the air photograph base to satellite imagery. Such scientists may find
themselves confronted with microwave or radar imagery or wish to use the
imagery for surveys and find themselves hindered by a lack of
understanding of the differences between radar imagery and optical
imagery. Unfortunately reference to much of the literature will not be
of very great help, many excellent text books on the theory and
interaction of microwaves, on instrument design and construction and on
the research carried out on specific target types exist, most of these
are however written for specialists who are usually physicists not earth
scientists.