I'm trying to get rid of the margins of maps generated using the 'maps' package in R. I get some of the way there by setting `par(mar=c(0,0,0,0))` and using the option border=0 in the `map()` function. But compared to e.g. a scatterplot with `mar=c(0,0,0,0)` there's still a lot of extra space. Here's some code to generate an example map, as well as a regular scatterplot for comparison.

```
library(maps)
x <- sample(360, 10)-180
y <- sample(160, 10)-80
x.boundary <- c(-180, 180, 0, 0)
y.boundary <- c(0, 0, -80, 80)

pdf("map.tmp.pdf", width=9, height=4)
par(mar=rep(0,4))
map("world", border=0, ylim=c(-80, 80), fill=TRUE, bg="gray", col="white")
points(x, y, pch=19, col="blue")
points(x.boundary, y.boundary, pch=19, col="red")
# map.axes()
dev.off()

pdf("scatter.tmp.pdf", width=9, height=4)
par(mar=rep(0,4))
plot(x, y, xlim=c(-180, 180), ylim=c(-80, 80), pch=19, col="blue")
points(x.boundary, y.boundary, pch=19, col="red")
dev.off()

```

If you uncomment the `map.axes()` function you can see that even with margins notionally suppressed, space has been reserved for the axes.

Any ideas much appreciated, this has been annoying me for ages.