This set of stats and geoms makes it possible to draw circle segments based
on a center point, a radius and a start and end angle (in radians). These
functions are intended for cartesian coordinate systems and makes it possible
to create circular plot types without using the
ggplot2::coord_polar()
coordinate system.
stat_arc(mapping = NULL, data = NULL, geom = "arc", position = "identity", na.rm = FALSE, show.legend = NA, n = 360, inherit.aes = TRUE, ...) geom_arc(mapping = NULL, data = NULL, stat = "arc", position = "identity", n = 360, arrow = NULL, lineend = "butt", na.rm = FALSE, show.legend = NA, inherit.aes = TRUE, ...) stat_arc2(mapping = NULL, data = NULL, geom = "path_interpolate", position = "identity", na.rm = FALSE, show.legend = NA, n = 360, inherit.aes = TRUE, ...) geom_arc2(mapping = NULL, data = NULL, stat = "arc2", position = "identity", n = 360, arrow = NULL, lineend = "butt", na.rm = FALSE, show.legend = NA, inherit.aes = TRUE, ...) stat_arc0(mapping = NULL, data = NULL, geom = "arc0", position = "identity", na.rm = FALSE, show.legend = NA, inherit.aes = TRUE, ...) geom_arc0(mapping = NULL, data = NULL, stat = "arc0", position = "identity", ncp = 5, arrow = NULL, lineend = "butt", na.rm = FALSE, show.legend = NA, inherit.aes = TRUE, ...)
mapping  Set of aesthetic mappings created by 

data  The data to be displayed in this layer. There are three options: If A A 
geom  The geometric object to use display the data 
position  Position adjustment, either as a string, or the result of a call to a position adjustment function. 
na.rm  If 
show.legend  logical. Should this layer be included in the legends?

n  the smoothness of the arc. Sets the number of points to use if the arc would cover a full circle 
inherit.aes  If 
...  Other arguments passed on to 
stat  The statistical transformation to use on the data for this layer, as a string. 
arrow  Arrow specification, as created by 
lineend  Line end style (round, butt, square). 
ncp  the number of control points used to draw the arc with curveGrob. Determines how well the arc approximates a circle section 
An arc is a segment of a line describing a circle. It is the fundamental visual element in donut charts where the length of the segment (and conversely the angular span of the segment) describes the proportion of an entety.
geom_arc understand the following aesthetics (required aesthetics are in bold):
x0
y0
r
start
end
color
size
linetype
alpha
lineend
The start coordinates for the segment
The end coordinates for the segment
The curvature of the curveGrob to match a circle
geom_arc_bar()
for drawing arcs with fill
# Lets make some data arcs < data.frame( start = seq(0, 2 * pi, length.out = 11)[11], end = seq(0, 2 * pi, length.out = 11)[1], r = rep(1:2, 5) ) # Behold the arcs ggplot(arcs) + geom_arc(aes(x0 = 0, y0 = 0, r = r, start = start, end = end, linetype = factor(r)))# Use the calculated index to map values to position on the arc ggplot(arcs) + geom_arc(aes(x0 = 0, y0 = 0, r = r, start = start, end = end, size = stat(index)), lineend = 'round') + scale_radius() # linear size scale# The 0 version maps directly to curveGrob instead of calculating the points # itself ggplot(arcs) + geom_arc0(aes(x0 = 0, y0 = 0, r = r, start = start, end = end, linetype = factor(r)))# The 2 version allows interpolation of aesthetics between the start and end # points arcs2 < data.frame( angle = c(arcs$start, arcs$end), r = rep(arcs$r, 2), group = rep(1:10, 2), colour = sample(letters[1:5], 20, TRUE) ) ggplot(arcs2) + geom_arc2(aes(x0 = 0, y0 = 0, r = r, end = angle, group = group, colour = colour), size = 2)