# 7. Altering oce Defaults

#### Dan Kelley (https://orcid.org/0000-0001-7808-5911)

#### 2024-08-17

Abstract. When R loads the `oce` package, certain defaults are defined for values such as the chosen equation of state, the expected timezone, etc. This vignette lists those defaults and explains how (with caution) they may be altered with the `~/.Rprofile` file.

The table below shows the default values of some quantities that `oce` uses in its processing. In most cases, these values make their way into the package as default values of function parameters via calls to the `getOption()` function. See `?plotTS` for an example.

Note that any of these values may be altered in the user’s `~/.Rprofile` file. For example, a user preferring that the old UNESCO equation of state be used in operations like plotting CTD data, might insert the following line in the `~/.Rprofile` file:

    options(oceEOS = "gsw")

but it should be noted that setting values in `~/.Rprofile` will render the user’s code non-reproducible (unless that file is provided along with the analysis code).

The preferred method is not to use `~/.Rprofile`, but instead to specify the desired properties as arguments to relevant functions. For example, calling `plotTS(..., eos="unesco")` instead of letting `eos` take on the default value of `"gsw"`. (It is the ability to specify a choice by such a parameter that is indicated in the right-most column of the following table.)

Name | Value | Selected by a function parameter
--- | --- | ---
`oceAbbreviateTimeRange` | `TRUE` | yes
`oceDebug` | `0` | yes
`oceDrawTimeRange` | `TRUE` | yes
`oceEOS` | `"gsw"` | yes
`oceMar` | `c(3, 3, 2, 2)` | yes
`oceMgp` | `c(2.0, 0.7, 0)` | yes
`oceTimeFormat` | `"%Y-%m-%d %H:%M:%S"` | yes
`oceTz` | `"UTC"` | yes
`oceUnitBracket` | `"["` | no
`webtide` | `"/usr/local/WebTide"` | yes