cplots (version 0.5-0)

cdotplot: Circular Stacked Dot Plot

Description

Function cdotplot can be used to plot 2-dimensional stacked dot plot for circular data.

Usage

cdotplot(
  x,
  nbins = 36,
  radius = 1,
  unit = NA,
  area.prop = TRUE,
  total.area = 1,
  m = NA,
  col = "lightblue",
  border = "skyblue4",
  xlim = NULL,
  ylim = NULL,
  main = NULL,
  x.legend = "bottomright",
  y.legend = NULL
)

Arguments

x

a circular data object that is fully defined by the user.

nbins

the number of bins of the circular histogram. Internally, it is rounded to a multiple of 4.

radius

the radius of the reference circle. If radius = 0, a rose diagram is produced; if radius > 0, a circular histogram is produced outside the reference circle.

unit

the number of observations represented by each dot. If unit > 1, it means that each dot represents multiple observations.

area.prop

logical; if TRUE, an area-proportional transformation is applied; if FALSE, a height-proportional transformationis applied.

total.area

a positive number specifying the total area under the density curve. If total.area = NULL, no scaling is applied, the plot is in the original scale. If area.prop = TRUE, the total area is automatically unity without scaling.

m

the number of points within each bin to plot the circular dot plot. The larger the number is, the smoother the plot looks.

col

the color to fill the bars.

border

the color of the border around the bars.

xlim

numeric vectors of length 2, giving the x coordinates ranges.

ylim

numeric vectors of length 2, giving the y coordinates ranges.

main

the main title (on top)

x.legend

x coordinate to plot the legend.

y.legend

y coordinate to plot the legend.

Value

No return value

Details

If the number of observations is relatively small, the usual circular stacked dot plot can be used with unit = 1. If the dataset is large, the dots may become too dense to visualize or count. Setting unit to be any positive integer to allow each dot to represent more than one observation. If the number of observations in one bin is not a multiple of the specified unit, a partial dot can be used to represent the remainder at the top of the bin.

References

Xu, D. and Wang, Y. (2020). Area-proportional Visualization for Circular Data. Journal of Computational and Graphical Statistics, 29, 351-357.

See Also

cbarplot, cdensity, chist

Examples

# NOT RUN {
# 30 observations from two von Mises distributions
library(circular)
x = c(rvonmises(10, circular(pi/4), 5), rvonmises(20, circular(pi), 20))
cdotplot(x)                 # area-proportional dot plot
cdotplot(x, area = FALSE)   # height-proportional dot plot

# 900 observations from two von Mises distributions
y = c(rvonmises(300, circular(pi/4), 5), rvonmises(600, circular(pi), 20))
cdotplot(y, nbins=76, unit = 10)      # area-proportional (partial) dot plot 
cdotplot(y, nbins=76, unit = 10, area = FALSE) # height-proportional

# }