ggplot2 (version 0.9.0)

coord_map: Map projections.

Description

This coordinate system provides the full range of map projections available in the mapproj package.

Usage

coord_map(projection = "mercator", ...,
    orientation = NULL, xlim = NULL, ylim = NULL)

Arguments

projection

projection to use, see mapproject for list

...

other arguments passed on to mapproject

orientation

projection orientation, which defaults to c(90, 0, mean(range(x))). This is not optimal for many projections, so you will have to supply your own.

xlim

manually specific x limits (in degrees of lontitude)

ylim

manually specific y limits (in degrees of latitude)

Details

This is still experimental, and if you have any advice to offer regarding a better (or more correct) way to do this, please let me know

Examples

if (require("maps")) {
# Create a lat-long dataframe from the maps package
nz <- data.frame(map("nz", plot=FALSE)[c("x","y")])
(nzmap <- qplot(x, y, data=nz, geom="path"))

nzmap + coord_map()
nzmap + coord_map(project="cylindrical")
nzmap + coord_map(project='azequalarea',orientation=c(-36.92,174.6,0))

states <- data.frame(map("state", plot=FALSE)[c("x","y")])
(usamap <- qplot(x, y, data=states, geom="path"))
usamap + coord_map()
# See ?mapproject for coordinate systems and their parameters
usamap + coord_map(project="gilbert")
usamap + coord_map(project="lagrange")

# For most projections, you'll need to set the orientation yourself
# as the automatic selection done by mapproject is not available to
# ggplot
usamap + coord_map(project="orthographic")
usamap + coord_map(project="stereographic")
usamap + coord_map(project="conic", lat0 = 30)
usamap + coord_map(project="bonne", lat0 = 50)
}