read.tdr: Read an TDR temperature-depth recorder data file

Description

Read an tdr temperature-depth recorder file, producing an object of type tdr.

Usage

read.tdr(file, from=1, to, by=1, type, tz=getOption("oceTz"),
         processingLog, debug=getOption("oceDebug"))

Arguments

file

a connection or a character string giving the name of the file to load.

from

indication of the first datum to read. This can a positive integer to indicate sequence number, the POSIX time of the first datum, or a character string that can be converted to a POSIX time. (For POSIX times, be careful about the tz

to

an indication of the last datum to be read, in the same
    format as from.  If to is missing, data will be read
    to the end of the file.

by

an indication of the stride length to use while walking
    through the file.  If this is an integer, then by-1
    profiles are skipped between each pair of profiles that is read.  If
    this is a string representing a time interval, in col

type

optional file type, presently only permitted to be rsk.

tz

time zone.  The default value, oceTz, is set to UTC 
    at setup.

processingLog

if provided, the action item to be stored in the
    log.  (Typically only provided for internal calls; the default that
    it provides is better for normal calls by a user.)

debug

a flag that can be set to TRUE to turn on debugging.

`Value`

An object of class "tdr", which is a
  list with elements detailed below.
dataa data table containing the time,
    temperature, and pressure data.
metadataa list containing the following items
    [object Object],[object Object],[object Object],[object Object]
processingLoga processingLog of processing, in the standard oce format.

`Implementation notes`

The end time for measurement
    (metadata$measurement.start) is inferred from the Logger time
    field in the header, not from Logging end.  The datasets available
    to the author suggest this is the proper scheme when the recorders are
    turned off manually before the end time that was programmed in.  In other
    cases, the assumption may or may not be correct.  Still, the end time for
    subsampling (metdata$subsample.end) should be correct.

`Details`

Read a TDR (temperature-depth recorder) file.  At the moment, four
    styles are understood: (1) text file with columns for temperature and
    pressure (with sampling times indicated in the header); (2) text file with
    four columns, in which the date the time of day are given in the first two
    columns, followed by the temperature, and pressure; (3) text file with five
    columns, in which depth in the water column is given after the pressure;
    (4) a new (and possibly still changeable) SQLite-based database format.

`See Also`

The documentation for tdr-class explains the structure of
    PT objects, and also outlines the other functions dealing with them.