How does one turn contour lines into filled contours?

Question

Does anyone know of a way to turn the output of contourLines polygons in order to plot as filled contours, as with filled.contours. Is there an ord

Answer 1

A solution that uses the raster package (which calls rgeos and sp). The output is a SpatialPolygonsDataFrame that will cover every value in your grid:

library('raster')
rr <- raster(t(volcano))
rc <- cut(rr, breaks= 10)
pols <- rasterToPolygons(rc, dissolve=T)
spplot(pols)

Here's a discussion that will show you how to simplify ('prettify') the resulting polygons.