Hi R-help

I am trying to mask the ocean from an image plot I have made.


Here is some example code:

library(mapdata)

image(x=110:155, y =-40:-10, z = outer(1:45, 1:30, "+"),

      xlab = "lon", ylab = "lat")

outline <- map("worldHires", plot=FALSE) # returns a list of x/y coords

xrange <- range(outline$x, na.rm=TRUE) # get bounding box

yrange <- range(outline$y, na.rm=TRUE)

xbox <- xrange + c(-2, 2)

ybox <- yrange + c(-2, 2)

# create the grid path in the current device

polypath(c(outline$x, NA, c(xbox, rev(xbox))),

     c(outline$y, NA, rep(ybox, each=2)),

     col="light blue", rule="evenodd")


As you can see, the polypath is on both sides of the country outline. Any
help is much appreciated.


Louise

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