Skip to contents

Rose diagram for circular (directional) data

Source: R/rose_diag_circ.R
rose_diag_circ.Rd

Draws a rose diagram (circular histogram) for a sample of angular measurements using ggplot2. Petal lengths are scaled to the square root of frequency so that petal area is proportional to count, reducing the visual dominance of the most frequent bin. Supports both vectorial data (0°–360°) and axial data (0°–180°), and optionally overlays the mean direction.

Usage

rose_diag_circ(
  x,
  data = NULL,
  width = 20,
  dir = 1,
  conf.level = 0.95,
  alpha = 0.7,
  fill.col = "blue",
  mean.col = "red",
  show.mean = T
)

Arguments

x

Numeric vector of angles in degrees, or an unquoted column name when data is supplied.

data

A data frame (or tibble) containing the column referenced by x. Default NULL (use x directly as a vector).

width

Numeric. Bin width in degrees. Default 20.

dir

Integer. Data type: 1 for vectorial data (full 0°–360° range, default); 0 for axial data (0°–180° range, e.g. strike or foliation— each measurement is mirrored to produce a symmetric bimodal diagram).

conf.level

Numeric. Confidence level passed to dir_stats_circ() for the mean-direction confidence cone shown in the subtitle. Default 0.95.

alpha

Numeric. Transparency of the petal fill (0 = fully transparent, 1 = fully opaque). Default 0.7.

fill.col

Character. Fill colour of the petals. Default "blue".

mean.col

Character. Colour of the mean-direction line(s). Default "red".

show.mean

Logical. If TRUE (default) a radial line is drawn at the mean direction and the mean ± confidence cone is shown in the plot subtitle; if FALSE neither is shown.

Value

A ggplot object containing the rose diagram. The plot caption reports the maximum bin percentage and the sample size; the subtitle (when show.mean = TRUE) reports the mean direction and its confidence cone in degrees.

References

Fisher, N. I. (1993). Statistical analysis of circular data. Cambridge University Press.

Davis, J. C. (2002). Statistics and data analysis in geology (3rd ed). J. Wiley.

Swan, A. R. H., & Sandilands, M. (1995). Introduction to geological data analysis. Blackwell Science.

See also

Other directional statistics: dir_aov_spher_ax(), dir_aov_spher_vec(), dir_stats_circ(), dir_stats_spher(), rose_diag_spher()

Examples

angles = c(255, 239, 222, 231, 199, 271, 222, 274, 228, 246,
           177, 199, 257, 201, 237, 209, 216, 180, 182, 250,
           219, 196, 197, 246, 218, 235, 232, 243, 232, 180,
           231, 254, 242, 149, 212, 210, 230, 205, 220, 268)
# Vectorial rose diagram with default settings
rose_diag_circ(angles)


# Axial data (strikes), wider bins, custom colours
rose_diag_circ(angles, dir = 0, width = 30,
               fill.col = "steelblue", mean.col = "magenta")


# From a data frame column, no mean line
df <- data.frame(azi = angles)
rose_diag_circ(azi, data = df, show.mean = FALSE)