etopo: Etopo colours

Description

Various ways to access the colors on the etopo color scale

Usage

etopo.colors(n)
scale_fill_etopo(...)
scale_color_etopo(...)

Arguments

n: number of colors to get from the scale. Those are evenly spaced within the scale.
...: passed to scale_fill_gradientn or scale_color_gradientn

Author

Jean-Olivier Irisson

Details

etopo.colors is equivalent to other color scales in R (e.g. grDevices::heat.colors, grDevices::cm.colors).

scale_fill/color_etopo are meant to be used with ggplot2. They allow consistent plots in various subregions by setting the limits of the scale explicitly.

Examples

Run this code

# load NW Atlantic data and convert to class bathy
data(nw.atlantic)
atl <- as.bathy(nw.atlantic)

# plot with base graphics
plot(atl, image=TRUE)

# using the etopo color scale
etopo_cols <- rev(etopo.colors(8))
plot(atl, image=TRUE, bpal=list(
  c(min(atl), 0, etopo_cols[1:2]),
  c(0, max(atl), etopo_cols[3:8])
))


# plot using ggplot2; in which case the limits of the scale are automatic
library("ggplot2")
ggplot(atl, aes(x=x, y=y)) + coord_quickmap() +
  # background
  geom_raster(aes(fill=z)) +
  scale_fill_etopo() +
  # countours
  geom_contour(aes(z=z),
    breaks=c(0, -100, -200, -500, -1000, -2000, -4000),
    colour="black", size=0.2
  ) +
  scale_x_continuous(expand=c(0,0)) +
  scale_y_continuous(expand=c(0,0))