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Plot Spherical Densities in a Spherical Projection

Source: R/stereonet_contours.R
stereo_contour.Rd

Kamb counts and densities on the sphere. contour plots the contour lines, contourf displays a contour plot with the areas between the contours filled, and image creates a dense grid of colored rectangles.

Usage

# S3 method for class 'spherical'
contour(
  x,
  add = FALSE,
  nlevels = 10L,
  density.params = list(),
  col.palette = viridis::viridis,
  col = NULL,
  col.params = list(),
  upper.hem = NULL,
  radius = NULL,
  ...
)

# S3 method for class 'sph_density'
contour(
  x,
  add = FALSE,
  nlevels = 10L,
  density.params = list(),
  col.palette = viridis::viridis,
  col = NULL,
  col.params = list(),
  upper.hem = NULL,
  radius = NULL,
  ...
)

contourf(
  x,
  add = FALSE,
  nlevels = 10L,
  density.params = list(),
  col.palette = viridis::viridis,
  col.params = list(),
  upper.hem = NULL,
  radius = NULL,
  ...
)

# S3 method for class 'spherical'
image(
  x,
  add = FALSE,
  nlevels = 10L,
  density.params = list(),
  col.palette = viridis::viridis,
  col.params = list(),
  upper.hem = NULL,
  radius = NULL,
  ...
)

# S3 method for class 'sph_density'
image(
  x,
  add = FALSE,
  nlevels = 10L,
  density.params = list(),
  col.palette = viridis::viridis,
  col.params = list(),
  upper.hem = NULL,
  radius = NULL,
  ...
)

Arguments

x

object of class "Vec3", "Line", "Ray", "Plane" or 'sph_density' (for plotting only).

add

logical. Whether the contours should be added to an existing plot.

nlevels

integer. Number of contour levels for plotting

density.params

list. Optional arguments passed to density.spherical(), such as FUN, n, sigma, and weights

col.palette

a color palette function to be used to assign colors in the plot.

col

colour(s) for the contour lines drawn. If NULL, lines are color based on col.palette.

col.params

list. Arguments passed to col.palette

upper.hem

logical. Whether the projection is shown for upper hemisphere (TRUE) or lower hemisphere (FALSE). Defaults to getOption("structr.upper.hem").

radius

numeric. Radius of circle. Defaults to getOption("structr.radius").

...

optional parameters passed to graphics::image() or graphics::contour().

Value

list containing the stereographic coordinates of the grid, the counts, and the density.

Note

Densities are plotted in the equal-area projection!

See also

Other stereo-plot: arrows(), fault-plot, lines(), plot-spherical, points.spherical(), stereo_cones, stereo_confidence(), stereo_lines(), stereo_point(), stereo_segment(), stereoplot(), stereoplot_guides(), stereoplot_ticks(), text.spherical()

Other density: density, density-funs

Examples

set.seed(20250411)
x <- rfb(100, mu = Line(120, 10), k = 5, A = diag(c(-1, 0, 1)))
contour(x)


x_density <- density(x)
contourf(x_density,
  col.params = list(direction = -1, begin = .05, end = .95, alpha = .75)
)
stereo_point(x, col = "black", pch = 21)


image(x)
stereo_point(x, col = "lightgrey", pch = 21)



# complete example:
par(mfrow = c(1, 2))
wp <- 6 / ifelse(is.na(example_planes_df$quality), 6, example_planes_df$quality)
my_planes <- Plane(example_planes_df$dipdir, example_planes_df$dip)
fabric_p <- vollmer(my_planes)["D"]
my_planes_eig <- ot_eigen(my_planes)

stereoplot(guides = TRUE, col = "grey96")
points(my_planes, col = "grey", pch = 16, cex = .5)
contour(my_planes, add = TRUE, weights = wp)
points(my_planes_eig$vectors[3, ], col = "black", pch = 16)
lines(my_planes_eig$vectors[3, ], ang = 90, col = "black", pch = 16)
title(
  main = "Planes",
  sub = paste0(
    "N: ", nrow(my_planes), " | Fabric strength: ", round(fabric_p, 2),
    "\nLambert equal area, lower hemisphere projection"
  )
)

my_lines <- Line(example_lines_df$trend, example_lines_df$plunge)
wl <- 6 / ifelse(is.na(example_lines_df$quality), 6, example_lines_df$quality)
fabric_l <- vollmer(my_lines)["D"]

stereoplot(guides = TRUE, col = "grey96")
points(my_lines, col = "grey", pch = 16, cex = .5)
contour(my_lines, add = TRUE, weights = wl)
points(sph_mean(my_lines, w = wl), col = "black", pch = 16)
title(
  main = "Lines",
  sub = paste0(
    "N: ", nrow(my_lines), " | Fabric strength: ", round(fabric_l, 2),
    "\nLambert equal area, lower hemisphere projection"
  )
)