geom_azimuthpoint: Azimuth + point visualization

In tectonicr: Analyzing the Orientation of Maximum Horizontal Stress

Azimuth + point visualization

Description

geom_azimuthpoint() draws line segments (spokes) like geom_azimuth(), but also places a point (marker) at the spoke's center ⁠(x, y)⁠.

Aesthetic rules:

• linewidth, linetype affect the spoke only

• shape affects the point only

• colour, alpha affect both spoke and point

• size sets the size of the point only

Usage

geom_azimuthpoint(
  mapping = NULL,
  data = NULL,
  stat = "identity",
  center = TRUE,
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE,
  size = 2,
  ...
)

Arguments

mapping	Set of aesthetic mappings created by ggplot2::aes().
data	A data frame. If NULL, the default, the data is inherited from the plot data as specified in the call to ggplot2::ggplot().
stat	The statistical transformation to use on the data. Defaults to "identity".
center	Logical; if TRUE spokes are centered on (x, y) using PositionCenterSpoke. If FALSE, behaves like ggplot2::geom_spoke() (line starts at (x, y)).
na.rm	If FALSE, the default, missing values are removed with a warning. If TRUE, missing values are silently removed.
show.legend	Logical. Should this layer be included in the legends?
inherit.aes	If FALSE, overrides the default aesthetics, rather than combining with them.
size	Size of the point marker (default = 2).
...	Other arguments passed on to geom_azimuth() and ggplot2::geom_point(). These may include arrow, fill, etc.

Value

A list of ggplot2 layers (spokes + points).

Aesthetics

geom_azimuthpoint() understands the following aesthetics (required aesthetics in bold):

• x

• y

• angle (in degrees, transformed internally; spoke only)

• radius (spoke only)

• colour (shared)

• alpha (shared)

• linewidth (spoke only)

• linetype (spoke only)

• shape (point only)

• size (point only, or via argument)

• fill (point only, for shapes that accept fill)

See Also

geom_azimuth(), ggplot2::geom_spoke(), ggplot2::geom_point()

Examples

set.seed(20250411)
df <- data.frame(
  x = runif(5), y = runif(5),
  angle_deg = rvm(5, mean = 90, kappa = 10),
  radius = runif(5, 0.1, 1),
  group = rep(1:2, length.out = 5)
)

if (require("ggplot2")) {
  ggplot(data = df, aes(x, y, angle = angle_deg, radius = radius)) +
    geom_azimuthpoint(aes(colour = factor(group), shape = factor(group)),
      linewidth = 1.1, linetype = "dashed",
      size = 3, alpha = 0.8
    )
}

tectonicr documentation built on Dec. 12, 2025, 9:06 a.m.