read.sealevel {oce}R Documentation

Read a sea-level data file

Description

Read a data file holding sea level data. BUG: the time vector assumes GMT, regardless of the GMT.offset value.

Usage

read.sealevel(file, tz=getOption("oceTz"), 
              processingLog, debug=getOption("oceDebug"))

Arguments

file

a connection or a character string giving the name of the file to load. See Details for the types of files that are recognized.

tz

time zone. The default value, oceTz, is set to UTC at setup. (If a time zone is present in the file header, this will supercede the value given here.)

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

set to TRUE to get debugging information during processing.

Details

This function starts by scanning the first line of the file, from which it determines whether the file is in one of two known formats: type 1, the format used at the Hawaii archive centre, and type 2, the comma-separated-value format used by the Marine Environmental Data Service. (The file type is inferred by checking for the existence of the string Station_Name on the first line of the file, indicating type 2.) If the file is in neither of these formats, the user might wish to scan it directly, and then to use as.sealevel to create a sealevel object.

Value

An object of class "sealevel", which is a list containing

data

: a list containing

time

time

eta

sea level [m]

metadata

: a list containing

header

the header line or lines. (This may prove helpful if detail extraction fails.)

year

year in which the observations were made.

station.number

identifier for the station.

station.version

see online docs at site mentioned in References.

station.name

name of station

region

a region code.

latitude

latitude, decimal degrees, positive north of equator.

longitude

longitude, decimal degrees, positive east of Greenwich.

GMT.offset

offset from GMT time. This is read directly from files of type 1. For files of type 2, the offset is inferred from the timezone, but this is a somewhat risky business, since timezone names are not standard.

decimation.method

see online docs at sites mentioned in References.

reference.offset

a reference offset; see online docs at sites mentioned in References.

reference.code

a reference code; see online docs at site mentioned in References.

units

unit of observations in the original file (normally "MM")

n

number of observations.

sampling.interval

hours between samples in the timeseries.

processingLog

: a log of processing, in the standard oce format.

Author(s)

Dan Kelley

References

The Hawaii archive site at http://ilikai.soest.hawaii.edu/uhslc/datai.html provides a graphical interface for downloading sealevel data in Type 1, with format as described at http://ilikai.soest.hawaii.edu/rqds/hourly.fmt (this link worked for years but failed at least temporarily on December 4, 2016). The MEDS repository (http://www.isdm-gdsi.gc.ca/isdm-gdsi/index-eng.html) provides Type 2 data.

See Also

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

Examples

## Not run: 
library(oce)
# this yields the sealevel dataset
sl <- read.oce("h275a96.dat")
summary(sl)
plot(sl)
m <- tidem(sl)
plot(m)

## End(Not run)

[Package oce version 0.9-18 Index]