Map alignment test

maptest.r

library(gcookbook)
library(ggplot2)

# Take a slice where z is equal to the minimum value of z
islice <- subset(isabel, z == min(z))

# Just the hurricane data
ggplot(islice, aes(x=x, y=y, fill=speed)) + geom_raster(alpha=.5) +
    scale_fill_continuous(na.value=NA)


# Get USA map data
usa <- map_data("usa")

# Map outline with hurricane data
ggplot(islice, aes(x=x, y=y)) +
    geom_raster(aes(fill=speed), alpha=.5) +
    scale_fill_continuous(na.value=NA) +
    geom_path(aes(x=long, y=lat, group=group), data=usa) +
    coord_cartesian(xlim = range(islice$x), ylim = range(islice$y)) 

For information about the data structures, you can do the following:

str(usa)
head(usa)
tail(usa)

str(islice)
head(islice)
tail(islice)

Data is from: http://www.vets.ucar.edu/vg/isabeldata/readme.html and http://vis.computer.org/vis2004contest/data.html