earpoints: Draws points on an equal area stereonet

Description

Draws points on an equal area stereonet (modified from RFOC package)

Usage

earpoints(
  dec,
  inc,
  hsphere = "b",
  double = FALSE,
  a = list(pch = 21, col = "black"),
  l = list(bg = "black"),
  h = list(bg = "grey"),
  u = list(bg = "white"),
  labels = NA,
  pos = 4,
  output = FALSE,
  plot = TRUE,
  xh = "WE"
)

Value

the x,y coordinates of each point in the projection

Arguments

dec: declination of the data; it is the angle from the north taken on an horizontal plane. It is measured clockwise from North and ranges from 0 to 360° (Tauxe 2010). Values outside this range are corrected by the incfix function.
inc: inclination of the data; it is the angle from the horizontal, is positive downward, and ranges from +90° for straight down to -90° for straight up (Tauxe, 2010). Values outside this range are corrected by the incfix function.
hsphere: the hemisphere onto which to project the data. The default is "b" for both: this useful in the case of oriented vectors rather than lines like for paleomagnetism. Other choices are "l" and "u" for lower and upper hemisphere.
double: whether to plot the equivalent point to one having an inclination of 0°(with dec = dec +180)
a, l, h, u: list of graphical parameters to feed points() for all points, or for the points of the upper (u) and lower (l) hemisphere, and of the samples having an inclination of 0° (h) (the three latter override a). See ?points help page for the possible arguments. See the example for illustration, and ?merge_list for further information.
labels: labels to each point
pos: position of each label (see text() help page)
output: whether to return an output (position of the points in the stereographic projection)
plot: whether to plot
xh: orientation of the x axis: can be 'WE' or 'SN'.

References

Snyder, John P., 1987, Map Projections-a working manual, USGS-Professional Paper, 383p. pages 185-186, RFOC package

Examples

Run this code

earnet()

h <- 17
m <- 11

if(m < 10) a <- "0" else a <- ""

title(paste("Il est ", h, "h",a,m, sep = ""))

i1 <- seq(40, 100, by = 10)
i2 <- seq(0, -100, by = -10)
d1 <- rep(h * 30 + m * 0.5, length(i1))
d2 <- rep(m*6, length(i2))

inc <- c(i1,i2)
dec <- c(d1,d2)

earpoints(dec,inc)