gf_contour: Formula interface to geom_contour() and geom_contour_filled()

In ggformula: Formula Interface to the Grammar of Graphics

Formula interface to geom_contour() and geom_contour_filled()

Description

ggplot2 can not draw true 3D surfaces, but you can use geom_contour(), geom_contour_filled(), and geom_tile() to visualise 3D surfaces in 2D.

These functions require regular data, where the x and y coordinates form an equally spaced grid, and each combination of x and y appears once. Missing values of z are allowed, but contouring will only work for grid points where all four corners are non-missing. If you have irregular data, you'll need to first interpolate on to a grid before visualising, using interp::interp(), akima::bilinear(), or similar.

Usage

gf_contour(
  object = NULL,
  gformula = NULL,
  data = NULL,
  ...,
  xlab,
  ylab,
  title,
  subtitle,
  caption,
  geom = "contour",
  stat = "contour",
  position = "identity",
  show.legend = NA,
  show.help = NULL,
  inherit = TRUE,
  environment = parent.frame()
)

gf_contour_filled(
  object = NULL,
  gformula = NULL,
  data = NULL,
  ...,
  xlab,
  ylab,
  title,
  subtitle,
  caption,
  geom = "contour_filled",
  stat = "contour_filled",
  position = "identity",
  show.legend = NA,
  show.help = NULL,
  inherit = TRUE,
  environment = parent.frame()
)

Arguments

object	When chaining, this holds an object produced in the earlier portions of the chain. Most users can safely ignore this argument. See details and examples.
gformula	A formula with shape y ~ x. Faceting can be achieved by including | in the formula.
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)).
...	Additional arguments. Typically these are (a) ggplot2 aesthetics to be set with attribute = value, (b) ggplot2 aesthetics to be mapped with attribute = ~ expression, or (c) attributes of the layer as a whole, which are set with attribute = value.
xlab	Label for x-axis. See also gf_labs().
ylab	Label for y-axis. See also gf_labs().
title, subtitle, caption	Title, sub-title, and caption for the plot. See also gf_labs().
geom	The geometric object to use to display the data, either as a ggproto Geom subclass or as a string naming the geom stripped of the geom_ prefix (e.g. "point" rather than "geom_point")
stat	The statistical transformation to use on the data for this layer, either as a ggproto Geom subclass or as a string naming the stat stripped of the stat_ prefix (e.g. "count" rather than "stat_count")
position	Position adjustment, either as a string naming the adjustment (e.g. "jitter" to use position_jitter), or the result of a call to a position adjustment function. Use the latter if you need to change the settings of the adjustment.
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.
show.help	If TRUE, display some minimal help.
inherit	A logical indicating whether default attributes are inherited.
environment	An environment in which to look for variables not found in data.

Value

a gg object

Specifying plot attributes

Positional attributes (a.k.a, aesthetics) are specified using the formula in gformula. Setting and mapping of additional attributes can be done through the use of additional arguments. Attributes can be set can be set using arguments of the form attribute = value or mapped using arguments of the form attribute = ~ expression.

In formulas of the form A | B, B will be used to form facets using facet_wrap() or facet_grid(). This provides an alternative to gf_facet_wrap() and gf_facet_grid() that is terser and may feel more familiar to users of lattice.

Evaluation

Evaluation of the ggplot2 code occurs in the environment of gformula. This will typically do the right thing when formulas are created on the fly, but might not be the right thing if formulas created in one environment are used to create plots in another.

See Also

ggplot2::geom_contour(), gf_density_2d()

Examples

gf_density_2d(eruptions ~ waiting, data = faithful, alpha = 0.5, color = "navy") |>
  gf_contour(density ~ waiting + eruptions, data = faithfuld, bins = 10, color = "red")
gf_contour_filled(density ~ waiting + eruptions, data = faithfuld, bins = 10,
    show.legend = FALSE) |>
  gf_jitter(eruptions ~ waiting, data = faithful, color = "white", alpha = 0.5,
    inherit = FALSE)

ggformula documentation built on Nov. 9, 2023, 5:08 p.m.