Draw automagic isopycnals — geom

Draws density contour lines ("isopycnals") as a ggplot2 layer. The x axis is assumed to be salinity; the y axis is assumed to be temperature. To use this geometry as standalone layer, you will need to specify which type of temperature (i.e., in-situ or conservative) and salinity (i.e., practical or absolute) are on these axes.

geom_isopycnal(
  mapping = NULL,
  data = NULL,
  ...,
  lineend = "butt",
  linejoin = "round",
  linemitre = 10,
  colour = "darkgray",
  size = 0.4,
  linetype = 1,
  alpha = NA,
  text.size = 3,
  family = "",
  salinity_type = c("practical", "absolute"),
  temperature_type = c("in-situ", "potential", "conservative"),
  ref_pressure = 0,
  ref_longitude = NULL,
  ref_latitude = NULL,
  trim_freezing = TRUE,
  breaks = pretty,
  labels = identity,
  label_placer = label_placer_isopycnal(),
  n_breaks = 5,
  n_sal = 200,
  n_temp = 200,
  eos = getOption("oceEOS", default = "gsw"),
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)

GeomIsopycnal

Arguments

mapping	Set of aesthetic mappings created by `aes()` or `aes_()`. If specified and `inherit.aes = TRUE` (the default), it is combined with the default mapping at the top level of the plot. You must supply `mapping` if there is no plot mapping.
data	The data to be displayed in this layer. There are three options: If `NULL`, the default, the data is inherited from the plot data as specified in the call to `ggplot()`. A `data.frame`, or other object, will override the plot data. All objects will be fortified to produce a data frame. See `fortify()` for which variables will be created. A `function` will be called with a single argument, the plot data. The return value must be a `data.frame`, and will be used as the layer data. A `function` can be created from a `formula` (e.g. `~ head(.x, 10)`).
...	Other arguments passed on to `layer()`. These are often aesthetics, used to set an aesthetic to a fixed value, like `colour = "red"` or `size = 3`. They may also be parameters to the paired geom/stat.
lineend, linejoin, linemitre, colour, size, linetype, alpha	Customize the appearance of contour lines. See `ggplot2::geom_path()` for details.
text.size, family	Customize the appearance of contour line labels. See `ggplot2::geom_text()` for details.
salinity_type	A salinity value. Use `salinity_type = "absolute"` to specify that `salinity` values are absolute salinities.
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	The latitude and longitude that should be used in seawater calculations if `eos` is "gsw".
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.
labels	A function or vector of labels with which isopycnals should be labeled.
label_placer	See `label_placer_isopycnal()` and `isoband::label_placer_minmax()` for ways to customize label placement. Use `NULL` for a default that avoids data passed to the layer.
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.
na.rm	If `FALSE`, the default, missing values are removed with a warning. If `TRUE`, missing values are silently removed.
show.legend	logical. Should this layer be included in the legends? `NA`, the default, includes if any aesthetics are mapped. `FALSE` never includes, and `TRUE` always includes. It can also be a named logical vector to finely select the aesthetics to display.
inherit.aes	If `FALSE`, overrides the default aesthetics, rather than combining with them. This is most useful for helper functions that define both data and aesthetics and shouldn't inherit behaviour from the default plot specification, e.g. `borders()`.

Format

An object of class GeomIsopycnal (inherits from Geom, ggproto, gg) of length 5.

Value

A ggplot2::layer()

Examples

library(ggplot2)
data(ctd, package = "oce")

ggplot(ctd, aes(salinity, temperature)) +
  geom_isopycnal() +
  geom_point()