Geology Reference
In-Depth Information
Before the introduction of GPS navigation, flight path recovery in airborne
surveys relied on interpolation between points identified photographically.
Necessarily, ground speed was assumed constant between these points, and
anomalies were displaced if this was not the case. Similar effects can now
be seen in data-logged ground surveys. Common reasons for slight dis-
placements of anomalies are that the observer either presses the key to
start recording at the start of the traverse, and then starts walking or, at the
end of the traverse, stops walking and only then presses the key to stop
recording. These effects can be avoided by insisting that observers begin
walking before the start of the traverse and continue walking until the end
point has been safely passed. If, however, speed changes are due to rugged
ground, the most that can be done is to increase the number of 'marker'
points.
