labelWithUnit creates a label with a unit, for graphical
display, e.g. by plot,section-method.
The unit is enclosed in square brackets, although setting
options(oceUnitBracket="(") will cause parentheses to be
used, instead. This function is intended mainly for use
within the package, and users should not rely on its behaviour being
unchangeable.
labelWithUnit(name, unit = NULL)character value naming a quantity.
a list containing items unit and (optionally) scale, only the
first of which, an expression(), is used. If unit is not provided,
then a default will be used (see “Details”).
labelWithUnit returns a language object, created with bquote(),
that that may supplied as a text string to legend(), mtext(), text(),
etc.
If name is in a standard list, then alterations are made as appropriate,
e.g. "SA" or "Absolute Salinity" yields an S with subscript A; "CT" or
"Conservative Temperature" yields an upper-case Theta, sigmaTheta
yields a sigma with subscript theta, sigma0 yields
sigma with subscript 0 (with similar for 1 through 4), "N2" yields "N" with
superscript 2, and "pressure" yields "p".
These basic hydrographic quantities have default units that will
be used if unit is not supplied (see “Examples”).
In addition to the above, several chemical names are recognized, but no unit is guessed for them, because the oceanographic community lacks agreed-upon standards.
If name is not recognized, then it is simply repeated in the
return value.
Other functions that create labels:
resizableLabel()
library(oce)
# 1. temperature has a predefined unit, but this can be overruled
labelWithUnit("temperature")
#> T * " [" * degree * C * "]"
labelWithUnit(
"temperature",
list(unit = expression(m / s), scale = "erroneous")
)
#> T * " [" * (m/s) * "]"
# 2. phosphate lacks a predefined unit
labelWithUnit("phosphate")
#> PO[4]
data(section)
labelWithUnit(
"phosphate",
section[["station", 1]][["phosphateUnit"]]
)
#> PO[4] * " [" * (mu * mol/kg) * "]"