WORKING GROUP 9 
RADFORTH 
511 
The six remaining engineering aspects in descending order of current significance are: 
Mining, Construction Technique, Agricultural Exploitation, Forestry, Town 
Site Planning and Natural Park Planning. Each involves appraisal for the 
terrain factors listed in Tables 1 and 2. The implications for which the terrain 
factors must be assessed obviously will be variable and some will be peculiar 
to the aspect involved. For instance, in Forestry, while the relationships 
prescribing for Off-road Access apply for evacuation of timber, etc., during 
summer operations where road and rail service is lacking, they do not obtain 
for fire prevention or establishing helicopter landing sites and pads. 
Also, variability in relationships may arise for a given engineering aspect. 
Thus, for Construction Technique, peat excavation and pipe-line laying have 
different meaning. The terrain factor designated as peat category (Tables 1,2) 
in the former activity is important for the liquifaction procedure, whereas in 
the latter it is important for bearing potential or perhaps insulation. 
These comparisons convey a significant warning for photo interpreters. This 
is that interpretation of organic terrain must not stop with the identification 
of the terrain factors. It must in addition account for both the terrain factors 
and the implications pertaining for the particular engineering aspect involved. 
Airphoto interpretation procedure 
The first step in procurement of engineering requirements was to determine 
the prevailing Air-form Patterns, figs. 1—5. 
Each Air-form Pattern was then expressed in terms of botanical and extra- 
biotic terrain factors obtained from comparative field study. These are shown 
in cols. 2 and 3, table 3. The botanical ones appear in two separate abridged 
lists in col. 2; those for the living mat on the left, those for the peat on the 
right. The extra-biotic ones are in col. 3. Only the fundamental terrain factors 
are listed and these are broadly described. Elaboration of them makes handy 
reference in the field notes or in an interpretive check list, sometimes termed a 
Key. The botanical ones have been classified and assigned letter symbols as 
recorded for ground level survey by MacFarlane [5]. 
The combined effects of the terrain factors for each Air-form Pattern are 
given in col. 4, table 3. They too are in abridged lists and are broadly 
expressed. Others which an engineer would know to be implicit may be ex 
pressed for convenience in hand-reference form. 
Detailed engineering survey, sampling, and design for given areas of organic 
terrain may now proceed if the combined effects of the terrain factors are 
assessed, col. 4; they are directly pertinent for engineering purposes. Air-form 
Patterns on the other hand are not; they are only a first step in interpretive 
procedure. 
An examination of table 3 will suggest that for a given engineering aspect, 
say Foundation Engineering, different Air-form Patterns have different im 
plication. Without a knowledge of total terrain effect, implementation of en-