Class to store echosounder data.
Accessing values. Data may be accessed as e.g.
echosounder[["time"]], echosounder[["depth"]],
echosounder[["a"]], etc. Items in metadata must be specified
by full name, but those in data may be abbreviated, so long as the
abbreviation is unique. In addition to the actual data, some derived fields
are also available: echosounder[["distance"]] calls
geodDist to compute calculate distance along the ship track,
echosounder[["Sv"]] returns a matrix of backscatter strength in DB,
and echosounder[["TS"]] returns a matrix of target strength in dB.
Assigning values. Everything that may be accessed may also be
assigned, e.g. echosounder[["time"]] <- 3600 + echosounder[["time"]]
adds an hour to time.
The data slot is a list containing
An infrequently updated record of the intrument position, in
timeSlow, longitudeSlow and latitudeSlow. These are
used in plotting maps with plot,echosounder-method.
An interpolated record of the instrument position, in time,
longitude, and latitude. Linear interpolation is used to
infer the longitude and latitude from the variables listed above.
depth, vector of depths of echo samples (measured positive
downwards in the water column). This is calculated from the inter-sample
time interval and the sound speed provided as the soundSpeed argument
to read.echosounder, so altering the value of the latter will
alter the echosounder plots provided by plot,echosounder-method.
The echosounder signal amplitude a, a matrix whose number of
rows matches the length of time, etc., and number of columns equal to
the length of depth. Thus, for example, a[100,] represents
the depth-dependent amplitude at the time of the 100th ping.
A matrix named b exists for dual-beam and split-beam cases.
For dual-beam data, this is the wide-beam data, whereas a is the
narrow-beam data. For split-beam data, this is the x-angle data.
A matrix named c exists for split-beam data, containing the
y-angle data.
In addition to these matrices, ad-hoc calculated matrices named
Sv and TS may be accessed as explained in the next section.
Other classes provided by oce: adp-class,
adv-class, argo-class,
bremen-class, cm-class,
coastline-class, ctd-class,
lisst-class, lobo-class,
met-class, oce-class,
odf-class, rsk-class,
sealevel-class,
section-class, topo-class,
windrose-class
Other things related to echosounder data: [[,echosounder-method,
[[<-,echosounder-method,
as.echosounder, echosounder,
findBottom,
plot,echosounder-method,
read.echosounder,
subset,echosounder-method,
summary,echosounder-method