chist {cplots}

Circular Histogram and Rose Diagram

Description

Function chist can be used to plot 2-dimensional histograms and rose diagrams for circular data.

Usage

chist(
  x,
  nbins = 36,
  radius = 1/sqrt(base::pi),
  area.prop = TRUE,
  prob = TRUE,
  total.area = 1,
  nlabels = 4,
  col = "lightblue",
  border = "skyblue4",
  m = NA,
  xlim = NULL,
  ylim = NULL,
  main = NULL
)

Arguments

x

a numeric vector storing angular values between 0 and 2 pi, or an object that can be coerced to.

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.

area.prop

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

prob

logical; if TRUE, the circular histogram graphic is a representation of probability densities; if FALSE, a representation of frequencies.

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.

nlabels

integer, for the number of levels for the density/frequency values to be plotted; if 0, no label is plotted

col

the color to fill the bars.

border

the color of the border around the bars.

m

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

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)

Value

No return value

Author(s)

Danli Xu <[e-mail]>, Yong Wang <[e-mail]>

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, cdotplot

Examples

# 600 observations from two von Mises distributions
library(circular)
x = c(rvonmises(200, circular(pi/4), 5), rvonmises(400, circular(pi), 20))

chist(x)                           # area-proportional circular histgram
chist(x, area = FALSE)             # height-proportional circular histgram
chist(x, radius=0)                 # area-proportional rose diagram
chist(x, radius=0, area=FALSE)     # height-proportional rose diagram

chist(x, prob=FALSE)               # labels for frequency
chist(x, nlabels=0)                # no label
chist(x, xlim=c(-1.7,1))           # use xlim
chist(x, area=FALSE, total=2)      # with scaling
chist(x, area=FALSE, total=NULL)   # without scaling