For each x value, geom_ribbon()
displays a y interval defined
by ymin
and ymax
. geom_area()
is a special case of
geom_ribbon
, where the ymin
is fixed to 0 and y
is used instead
of ymax
.
geom_ribbon(
mapping = NULL,
data = NULL,
stat = "identity",
position = "identity",
...,
na.rm = FALSE,
orientation = NA,
show.legend = NA,
inherit.aes = TRUE,
outline.type = "both"
)geom_area(
mapping = NULL,
data = NULL,
stat = "identity",
position = "stack",
na.rm = FALSE,
orientation = NA,
show.legend = NA,
inherit.aes = TRUE,
...,
outline.type = "upper"
)
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)
).
The statistical transformation to use on the data for this layer, as a string.
Position adjustment, either as a string, or the result of a call to a position adjustment function.
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.
If FALSE
, the default, missing values are removed with
a warning. If TRUE
, missing values are silently removed.
The orientation of the layer. The default (NA
)
automatically determines the orientation from the aesthetic mapping. In the
rare event that this fails it can be given explicitly by setting orientation
to either "x"
or "y"
. See the Orientation section for more detail.
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.
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()
.
Type of the outline of the area; "both"
draws both the
upper and lower lines, "upper"
/"lower"
draws the either lines only.
"full"
draws a closed polygon around the area.
This geom treats each axis differently and, thus, can thus have two orientations. Often the orientation is easy to deduce from a combination of the given mappings and the types of positional scales in use. Thus, ggplot2 will by default try to guess which orientation the layer should have. Under rare circumstances, the orientation is ambiguous and guessing may fail. In that case the orientation can be specified directly using the orientation
parameter, which can be either "x"
or "y"
. The value gives the axis that the geom should run along, "x"
being the default orientation you would expect for the geom.
geom_ribbon()
understands the following aesthetics (required aesthetics are in bold):
x
or y
ymin
or xmin
ymax
or xmax
alpha
colour
fill
group
linetype
size
Learn more about setting these aesthetics in vignette("ggplot2-specs")
.
An area plot is the continuous analogue of a stacked bar chart (see
geom_bar()
), and can be used to show how composition of the
whole varies over the range of x. Choosing the order in which different
components is stacked is very important, as it becomes increasing hard to
see the individual pattern as you move up the stack. See
position_stack()
for the details of stacking algorithm.
geom_bar()
for discrete intervals (bars),
geom_linerange()
for discrete intervals (lines),
geom_polygon()
for general polygons
# NOT RUN {
# Generate data
huron <- data.frame(year = 1875:1972, level = as.vector(LakeHuron))
h <- ggplot(huron, aes(year))
h + geom_ribbon(aes(ymin=0, ymax=level))
h + geom_area(aes(y = level))
# Orientation cannot be deduced by mapping, so must be given explicitly for
# flipped orientation
h + geom_area(aes(x = level, y = year), orientation = "y")
# Add aesthetic mappings
h +
geom_ribbon(aes(ymin = level - 1, ymax = level + 1), fill = "grey70") +
geom_line(aes(y = level))
# }
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