as.sealevel {oce} | R Documentation

## Coerce Data Into a Sealevel Object

### Description

Coerces a dataset (minimally, a sequence of times and heights) into a sealevel dataset. The arguments are based on the standard data format, as were described in a file formerly available at [1].

### Usage

    as.sealevel(elevation, time, header = NULL, stationNumber = NA,
      stationVersion = NA, stationName = NULL, region = NULL, year = NA,
      longitude = NA, latitude = NA, GMTOffset = NA, decimationMethod = NA,
      referenceOffset = NA, referenceCode = NA, deltat)

### Arguments

`elevation` | a list of sea-level heights in metres, in an hourly sequence.
`time` | optional list of times, in POSIXct format. If missing, the list will be constructed assuming hourly samples, starting at 0000-01-01 00:00:00.
`header` | a character string as read from first line of a standard data file.
`stationNumber` | three-character string giving station number.
`stationVersion` | single character for version of station.
`stationName` | the name of station (at most 18 characters).
`region` | the name of the region or country of station (at most 19 characters).
`year` | the year of observation.
`longitude` | the longitude in decimal degrees, positive east of Greenwich.
`latitude` | the latitude in decimal degrees, positive north of the equator.
`GMTOffset` | offset from GMT, in hours.
`decimationMethod` | a coded value, with 1 meaning filtered, 2 meaning a simple average of all samples, 3 meaning spot readings, and 4 meaning some other method.
`referenceOffset` | ?
`referenceCode` | ?
`deltat` | optional interval between samples, in hours (as for the `ts` timeseries function). If this is not provided, and `t` can be understood as a time, then the difference between the first two times is used. If this is not provided, and `t` cannot be understood as a time, then 1 hour is assumed.

### Value

An object of `class` `"sealevel"` (for details, see `read.sealevel`).

### Author(s)

Dan Kelley

### References

`http://ilikai.soest.hawaii.edu/rqds/hourly.fmt` (this link worked for years but failed at least temporarily on December 4, 2016).

### See Also

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

Other things related to `sealevel` data: `[[,sealevel-method`, `[[<-,sealevel-method`, `plot,sealevel-method`, `read.sealevel`, `sealevel-class`, `sealevelTuktoyaktuk`, `sealevel`, `subset,sealevel-method`, `summary,sealevel-method`

### Examples

    library(oce)

    # Construct a year of M2 tide, starting at the default time
    # 0000-01-01T00:00:00.
    h <- seq(0, 24*365)
    elevation <- 2.0 * sin(2*pi*h/12.4172)
    sl <- as.sealevel(elevation)
    summary(sl)

    # As above, but start at the Y2K time.
    time <- as.POSIXct("2000-01-01") + h * 3600
    sl <- as.sealevel(elevation, time)
    summary(sl)

[Package oce version 0.9-22 Index]