Plot an indicatrix

Source: R/tissot.R

Draws a single Tissot indicatrix ellipse on the current plot. The ellipse shows the distortion of a unit circle under the map projection. Optional overlays include a reference unit circle, and lambda/phi direction axes.

# S3 method for class 'indicatrix'
plot(
  x,
  scale = 1e+05,
  n = 72,
  col = "#FF990055",
  border = "black",
  add = TRUE,
  show.axes = TRUE,
  show.circle = TRUE,
  ...
)

Arguments

x

an indicatrix object (from indicatrix())

scale

scaling factor for the ellipse size in projected units

n

number of points on the ellipse

col

fill colour for the ellipse

border

border colour

add

logical; add to existing plot?

show.axes

TRUE, FALSE, or a named list of graphical parameters for the direction lines. Defaults: list(col.lambda = "red", col.phi = "blue", lwd = 1.5).

show.circle

TRUE, FALSE, or a named list of graphical parameters for the reference circle. Defaults: list(col = adjustcolor("white", alpha.f = 0.6), border = "grey70", lwd = 2.5, lty = 2).

...

passed to graphics::polygon()

Value

The input x, invisibly.

Details

show.circle and show.axes accept TRUE (use defaults), FALSE (hide), or a named list of graphical parameters to override defaults. For example, show.circle = list(border = "blue", lty = 3).