xyz.to.enu.adv(x, declination=0, debug=getOption("oce.debug"))"adv".x. The algorithm is
similar to that used for Teledyne/RDI ADCP units, taking into account
the different definitions of heading in the two cases. Generally, the transformation must be done on a time-by-time basis,
which is a slow operation. However, this function checks whether the
vectors for heading, pitch and roll, are all of unit length, and in
that case, the calculation time is reduced by an order of magnitude.
This situation of singleton vectors is not uncommon, because the
orientation data can be noisy, requiring the user to substitute
cleaned-up values, and if the instrument is moored on a steady
platform, it makes sense to supply single values. Note that the
angles are held in data$ts.slow for Nortek instruments and
data$ts for Sontek instruments.
To indicate the change in coordinate, the value of
metadata$oce.orientation is changed from xyz to
enu, and this is noticed by e.g. plot.adv.
read.adv for notes on functions relating to
"adv" objects.