41. 
AIRBORNE GEOPHYSICAL SURVEY PROJECTS 
  
The last but not least application of Remote Sen- 
sing Technology in Brazil is in mineral prospection by the use of 
Aeromagnetometers, aeroscintilometers, aerogamaespectrometers and 
aeroelectromagnetomers. 
Overone million linear kilometers have been flown 
from 1970 to 1975 and another million is predicted for 19765, dis- 
tribute all over the brazilian territory. 
Data acquisition is undertaken by private compani 
es sub-contracted by two mixt (part-private, part-government) com- 
panies in charge of the airborne-geophysical surveys for prospectior 
of ferrous group (aeromagnetomers), non-ferrous group of minerals 
(electromagnetometers) and radioactive minerals (aeroscintilometers 
and aerogamaespectrometers). 
Lines are flown from a medium height of 135 m fol 
lowing the terrain relief laid out over a semi-controlled mosaic - 
spaced one or two quilometers depending on the degree of probabili 
ty of mineral ore bodies be encountered. 
Data process is done in electronic computers using 
packages of programs specifically developed for refinement of da- 
ta and their interpolation aiming at the production of iso-value - 
contour maps in order to visualise eventual anomalies very frequen 
tly caused by a mineral occurence. 
Contours are automatically plotted in programable 
electronic plotters. 
Data interpretation is done by geophysicists specia 
lized in this kind of activity, using the analog profiles resulting 
from the airborne equipment, the contour maps and the existing geo- 
logic maps or the results of a photo-geologic interpretation.