This class is for data stored in a format used at Bremen.
It is somewhat similar to the odf, in the sense
that it does not apply just to a particular instrument.
Although some functions are provided for dealing with these
data (see “Details”), the most common action is to read the
data with read.bremen(), and then to coerce the object to
another storage class (e.g. using as.ctd() for CTD-style
data) so that specialized functions can be used thereafter.
dataAs with all oce objects, the data slot
for bremen objects is a
list containing the main data for the object.
metadataAs with all oce objects, the metadata slot
for bremen objects is a list containing
information about the data or about the object itself.
processingLogAs with all oce objects, the processingLog slot
for bremen objects is a
list with entries describing the creation and evolution
of the object. The contents are updated by various oce functions to
keep a record of processing steps. Object summaries and
processingLogShow() both display the log.
Although the [[<- operator may permit modification of the contents
of bremen objects (see [[<-,bremen-method),
it is better to use oceSetData() and oceSetMetadata(),
because those functions save an entry in the processingLog
that describes the change.
The full contents of the data and metadata slots of a bremen
object may be retrieved in the standard R way using slot(). For
example slot(o,"data") returns the data slot of an object named o,
and similarly slot(o,"metadata") returns
the metadata slot.
The slots may also be obtained with the [[,bremen-method
operator, as e.g. o[["data"]] and o[["metadata"]], respectively.
The [[,bremen-method operator can also
be used to retrieve items from within the data and metadata slots.
For example, o[["temperature"]] can be used to retrieve temperature
from an object containing that quantity. The rule is that a named
quantity is sought first within the object's metadata slot,
with the data slot being checked only if metadata does not
contain the item. This [[ method can also be used to get
certain derived quantities, if the object contains sufficient
information to calculate them. For example, an object that holds
(practical) salinity, temperature and pressure, along with
longitude and latitude, has sufficient information to compute
Absolute Salinity, and so o[["SA"]] will yield the
calculated Absolute Salinity.
It is also possible to find items more directly, using oceGetData() and
oceGetMetadata(), but neither of these functions can
retrieve derived items.
Dan Kelley
Other classes provided by oce:
adp-class,
adv-class,
argo-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,
xbt-class
Other things related to bremen data:
[[,bremen-method,
[[<-,bremen-method,
plot,bremen-method,
read.bremen(),
summary,bremen-method