emphasizing a smaller quantity of data. It is important to remember that the 
other filters must be used to obtain the information screened out by the red 
filter. 
Another parameter which has to be considered i§ the film sensitivity 
to the different wave length radiations. The aerographic infrared film with 
Wratten 89B filter is sensitive to wave length longer than 0.7y. This band 
gives the plant condition from the physiological point of view. Thus for the 
healthy dense plants the response will be dark on the positive transparency. 
If the plant is not dense enough, therefore, permitting the film to receive soil 
high reflectance in the visible portion, it will be presented as light red. If 
the plant loses infrared reflectance the positive image will be more cyan to 
green. Figure 3, shows this reaction on the area covered by dry ( Melinis) which 
appears green on the color infrared image and dark on the black and white. 
Areas covered by ( Imperata ) appear pink to white because of the lightly dense 
canopy cover on the colored infrared and, in light gray scales on the black 
and white infrared image. The high moisture content areas appear in darker 
tones because of the low soil reflectance. A comparison between the plant 
reflectance patterns, and filter transmissions curves allowed the establishment 
of an interpretation key to obtain the requested results. 
The color infrared film has three sensitive layers. The bottom one 
is sensitive to red reflected radiation and responds in magenta color on the 
positive transparency. The middle layer is green sensitive and shows up yellow 
on the positive image. The top layer is infrared sensitive and shows in cyan 
on the positive image (6). 
RESULTS 
Fig. 4 shows the final map of rangeland capability for grazing. The 
area could be classified into four classes: 
Class A: Areas which are able to receive animals for grazing immediately during 
the rainy season. These areas are covered by such palatable species as 
Capim gordura ( Melinis minutiflora) , Coloniao ( Panicum maximum) , or 
Napir elefente ( Pannisetum purpureum ). 
Class B: Areas which are not available for grazing because they are occupied by 
unpalatable species. These invaders are mainly Sape ( Imperata brasi- 
liensis ), Vassorinha ( Bacchoris rufescences) . Batatis ( Paspalum 
notatum ) or other bushes. The range manager can think about improving 
his range by controlling the invaders. 
Class C: Areas which are in need of land reclamation before grazing because 
they are suffering from drainage problems. These are classified by 
vegetation type cover. Taboa ( Thypha sp.) is the indicator of high 
water table soils.