autoplot.bathy: Ploting bathymetric data with ggplot

Description

Plots contour or image map from bathymetric data matrix of class bathy with ggplot2

Usage

# S3 method for bathy
autoplot(x, geom="contour", mapping=NULL, coast=TRUE, ...)

Arguments

x: bathymetric data matrix of class bathy, imported using read.bathy
geom: geometry to use for the plot, i.e. type of plot; can be `contour', `tile' or `raster'. contour does a contour plot. tile and raster produce an image plot. tile allows true geographical projection through coord_map. raster only allows approximate projection but is faster to plot. Names can be abbreviated. Geometries can be combined by specifying several in a vector.
mapping: additional mappings between the data obtained from calling fortify.bathy on x and the aesthetics for all geoms. When not NULL, this is a call to aes().
coast: boolean; wether to highlight the coast (isobath 0 m) as a black line
...: passed to the chosen geom(s)

Author

Jean-Olivier Irisson

Details

fortify.bathy is called with argument x to produce a data.frame compatible with ggplot2. Then layers are added to the plot based om the argument geom. Finally, the whole plot is projected geographically using coord_map (for geom="contour") or an approximation thereof.

Examples

Run this code

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

  # basic plot
if (FALSE) {
  library("ggplot2")
	autoplot.bathy(atl)

  # plot images
	autoplot.bathy(atl, geom=c("tile"))
	autoplot.bathy(atl, geom=c("raster")) # faster but not resolution independant

  # plot both!
	autoplot.bathy(atl, geom=c("raster", "contour"))

  # geom names can be abbreviated
	autoplot.bathy(atl, geom=c("r", "c"))

  # do not highlight the coastline
	autoplot.bathy(atl, coast=FALSE)
    
  # better colour scale
  	autoplot.bathy(atl, geom=c("r", "c")) +
    scale_fill_gradient2(low="dodgerblue4", mid="gainsboro", high="darkgreen")

  # set aesthetics
	autoplot.bathy(atl, geom=c("r", "c"), colour="white", size=0.1)
  
  # topographical colour scale, see ?scale_fill_etopo
	autoplot.bathy(atl, geom=c("r", "c"), colour="white", size=0.1) + scale_fill_etopo()
  	
	# add sampling locations
	data(metallo)
  last_plot() + geom_point(aes(x=lon, y=lat), data=metallo, alpha=0.5)

  # an alternative contour map making use of additional mappings
  # see ?stat_contour in ggplot2 to understand the ..level.. argument
	autoplot.bathy(atl, geom="contour", mapping=aes(colour=..level..))
}