---
title: "7. Altering oce Defaults"
author: "Dan Kelley (https://orcid.org/0000-0001-7808-5911)"
date: "`r Sys.Date()`"
output:
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vignette: >
  %\VignetteIndexEntry{7. Altering oce Defaults}
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---

**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:
```{r eval=FALSE}
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                              |

