useHeading: Replace the heading for one instrument with the heading for another
Description
Replace the heading angles in one oce object with that from
another, possibly with a constant adjustment.
Usage
useHeading(b, g, add=0)
Arguments
b
object holding data from an instrument whose heading is bad, but
whose other data are good.
g
object holding data from an instrument whose heading is good, and
should be interpolated to the time base of b.
add
an angle, in degrees, to be added to the heading.
Value
A copy of b, but with b$data$heading replaced with heading
angles that result from linear interpolation of the headings in g, and
then adding the angle add.