Generate an 'isolines' object representing isopycnals

isopycnal_isolines(
  salinity,
  temperature,
  ref_pressure = 0,
  ref_longitude = NULL,
  ref_latitude = NULL,
  salinity_type = c("practical", "absolute"),
  temperature_type = c("in-situ", "potential", "conservative"),
  trim_freezing = TRUE,
  breaks = pretty,
  n_breaks = 5,
  n_sal = 200,
  n_temp = 200,
  eos = getOption("oceEOS", default = "gsw")
)

Arguments

salinity, salinity_type	A salinity value. Use `salinity_type = "absolute"` to specify that `salinity` values are absolute salinities.
temperature, temperature_type	A temperature value. Use `temperature_type = "conservative"` to specify that these values are not in-situ temperature.
ref_pressure	The pressure that should be used to calculate density contours in dbar.
ref_longitude, ref_latitude	The latitude and longitude that should be used in seawater calculations if `eos` is "gsw".
trim_freezing	Don't draw contours outside the freezing region.
breaks	A numeric vector or function used to generate breaks from objects.
n_breaks	Passed to `breaks` if `breaks` is a function.
n_sal	Number of points with which contours should be approximated on the salinity axis.
n_temp	Number of points with which contours should be approximated on the temperature axis.
eos	The equation of state: one of "unesco" or "gsw". See `oce::swRho()` for details.

Value

An object returned by isoband::isolines(). The x values of the output refer to salinity and the y values of the output refer to temperature.

Examples

data(ctd, package = "oce")
isolines <- isopycnal_isolines(ctd[["salinity"]], ctd[["temperature"]])

plot(ctd[["salinity"]], ctd[["temperature"]])
for (line in isolines) {
  lines(line)
}