contourPlot {contourPlot}

Plot a contour map

Description

Takes x,y,z co-ordinates and plots them on a contour map. Smoothing and interpolation is done by means of fitting a spline to the data.

Usage

contourPlot(
  x,
  y,
  z,
  nx = length(unique(x)),
  main = NULL,
  axis = TRUE,
  legend = TRUE,
  xlab = "",
  ylab = "",
  col = NULL,
  breaks = NULL,
  nlevels = 10,
  legend_pos = 4
)

Arguments

x

a vector of x co-ordinates

y

a vector of y co-ordinates

z

a vector of z co-ordinates representing the height of the contours

nx

The number of pixels that will be in final plot. default is length(unique(x))

main

Title of plot

axis

logical if TRUE displays the axes of the plot

legend

logical if TRUE displays the legend

xlab

label on x axis

ylab

label on y axis

col

list of colors to be applied to contours.

breaks

list of values indicating the contour ranges

nlevels

useful if breaks and col are left as null. Sets the number of levels of the contours to be plotted

legend_pos

set position of the colour bar. Default = 4.

Value

A contour plot (similar to those in base, additional elements can be added using lines, points functions etc.

Examples

x <- Volcontour$x
y <- Volcontour$y
z <- Volcontour$z

contourPlot(x = x, y = y, z = z)

# A smoother contour
contourPlot(x = x, y = y, z = z, nx = 500)

# Changing breaks and colours
breaks = pretty(c(min(z),max(z)))
col = brewer.pal(n = length(breaks)-1, "Blues")
contourPlot(x = x, y = y, z = z, nx = 500, breaks = breaks, col = col)

# add lines
lines(circle(0, 0, 26.5))