earpoints {StratigrapheR}

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"
)

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'.

Value

the x,y coordinates of each point in the projection

References

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

See Also

earnet, earplanes and incfix

Examples

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)