— 1404 - 
Minnesota and California, with a Wild RC-8 camera and Kodak Plus-X, Double-X 
and Ektachrome MS Aerographic films. 
In the following few years, impetus was given to the civilian use of high- 
flight photography in the USA through the provision of photography using 
RB-57 and U-2 aircraft, The objective was to provide a basis for assessing 
the value of photographs taken by the Apollo-9 satellite (e.g. Carneggie 
et al, 1969), to assist in developing the programme of the polar orbiting 
NASA Landsat-1 launched in August 1972 (known at that time as ERTS-1) and to 
provide comparative information for Landsat studies (e.g. Lundelius et al, 1973; 
Carneggie & De Gloria, 1973). Unfortunately, interest in the wider use of 
HFAP seems to have been eclipsed by and virtually ceased with the sudcessful 
launching and operation of Landsat 1; and only recently has there been 
renewed interest in HFAP, both for thematic mapping and photogrammetric 
purposes. This probably results, at least partly, from some disappointing 
experiences in attempting to apply Landsat products to resource surveys. 
III. PREVIOUS RESULTS 
Comparative studies were made in the USA between Apollo-9 photographs and 
HFAP of agricultural test sites in Arizona (Carneggie et al, 1969; Draeger 
and Pettinger, 1972; Draeger et al 1974), in California (Johnson, Do 
in Nevada (Tueller and Lorain, 1973) and in Texas (Lundelius et al, 1973 
Several film-filter combinations were tested from altitudes of about 18,450 me 
Results indicated that Infrared Ektachrome (type 8443/15) was, in general; 
superior for land-use and agricultural studies to other film-filter 
combinations, since it has the qualities of both providing the imagery in 
colour and with better resolution due to the better haze penetration. 
Analysis of the Arizona imagery showed that Landsat imagery and HFAP imagery 
could both be used to classify land-use features in about 10 broad types 
(i.e. Category I ¢ urban, rangeland, agricultural, forest, water eS 
subsequently into finer classes (Category II land-use types included?deciduous 
evergreen and mixed forests; grass, savanna, chaparaal and desert as grazin 
classes and pasture, arable, croplands and orchards as agricultural ets. 
However, this breakdown was achieved mainly with HFAP photographs, due to 
their much higher resolution and hence easier and more detailed identification 
of surface features. 
Agricultural studies in Arizona at the time of Apollo satellite photography 
drew attention to the importance of crop calendars and season of HFAP for 
successful identification of small grain crops. It was found for example, 
that normal colour (Ektachrome ) provided lower variance ratios for 'wheat" 
identification than for other film types; but sampling errors were undesirably 
high, i.e. 11% (barley) to 13% Re a ca 8% for small grains and difficulty 
was even experienced on occasions in separating wheat from alf-alfa, 
It is also interesting to note the comment by Draeger and Pettinger (1972) that 
'although the resolution of the high-altitude photographs was greater than that 
of space photographs (Apollo-9) of the same area, the improvement was not 
sufficient to permit detection of image detail which is necessary for increased 
    
   
  
  
  
  
   
  
  
  
  
  
  
   
  
   
  
  
  
   
  
  
  
    
   
  
   
  
   
  
  
  
   
  
  
  
  
  
   
    
  
  
   
  
   
  
  
   
   
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