oce (version 0.1-80)

read.adp: Read an ADP data file

Description

Read an ADP data file, producing an object of type adp.

Usage

read.adp(file, from=0, to, by=1,
          type=c("rdi", "nortek", "sontek"),
          debug=getOption("oce.debug"), monitor=TRUE, log.action)
read.adp.rdi(file, from=0, to, by=1,
              type=c("workhorse"),
              debug=getOption("oce.debug"), monitor=TRUE, log.action)
read.adp.nortek(file, from=0, to, by=1,
                type=c("aquadopp high resolution"),
                debug=getOption("oce.debug"), monitor=TRUE, log.action)
read.adp.sontek(file, from=0, to, by=1,
                type=c("adp"),
                withHeader=FALSE,
                debug=getOption("oce.debug"), monitor=TRUE, log.action)

Arguments

file

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

from

number of profiles to skip at start, or the POSIXt time at which to start reading. See Examples, and make careful note of the use of the tz argument.

to

optional number of profiles to read, or the last POSIXt time to read.

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

a character string indicating th type of file.

withHeader

a boolean indicating whether the file has a proper header (NOT SUPPORTED YET) or is a partial file, chopped out into smaller time chunks with a deck unit (SUPPORTED.

debug

a flag that turns on debugging. Set to 1 to get a moderate amount of debugging information, or to 2 to get more.

monitor

boolean, set to TRUE to provide an indication (with numbers and dots) of every profile read.

log.action

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.)

Value

• An object of class "adp", which contains measurements made with an ADP device. The value of metadata$coordinate is set to "beam", a fact that is used in other steps in processing. For information on data stored in the object, see Details.

Details

Reads a binary-format ADP file. Two types can be handled at the moment: the Teledyne-RDI (2007) Workhorse instrument using firmware version 16.28, and the NorTek Aquadopp High Resolution profiler. read.adp may also work on other RDI units, but this has not been tested. It definitely does not work on other NorTek units, because the binary format is different for each.

There are three types of element stored in the result's data, namely space-series, time-series, and matrix. These are contained within lists named data$ss, data$ts and data$ma, and their contents are as follows. [object Object],[object Object],[object Object] In addition to the data entry, the metadata entry holds general information about such things as beam geometry, etc.

References

Teledyne-RDI, 2007. WorkHorse commands and output data format. P/N 957-6156-00 (November 2007).

Information on the Nortek profiler is available at http://www.nortekusa.com/. (One must join the site to see the manuals, so no citation is provided here.)

See Also

The generic function read.oce provides an alternative to this. An adp object may be summarized with summary.adp, and plotted with plot.adp.

Several functions are provided to manipulate adp objects. For example, in many research applications, the records are stored in beam coordinates, instead of the further-processed forms such as instrument or enu coordinates. Accordingly, adp.beam2xyz is provided, convert the velocity portions of adp objects from beam coordinates to xyz-based (also called ship-based or instrument-based) coordinates. Similarly, adp.xyz2enu converts from xyz to enu coordinates, taking into account the varying orientation of an instrument attached to a ship or a mobile mooring. For applications in which enu-based coordinates are not desired (e.g. if a coordinate is to be aligned with the local coastline or a mean current), adp.enu2other is provided, to convert from enu coordinates to another coordinate system.

Another convenience function is adp.beam.attenuate, which performs a correction for $r^2$ beam spreading.

Examples

library(oce)
# A day sampled at 1/2 hour interval.  Note the timezone.
d <- read.oce("~/SL08F001.000", 
               from=as.POSIXct("2008-06-26", tz="UTC"),
               to=as.POSIXct("2008-06-27", tz="UTC"), 
               by="30:00")
summary(d)
plot(d)