contour.RdContour plot of a RasterLayer.
# S4 method for class 'RasterLayer'
contour(x, maxpixels=100000, ...)Raster* object
maximum number of pixels used to create the contours
any argument that can be passed to contour (graphics package)
r <- raster(system.file("external/test.grd", package="raster"))
plot(r)
contour(r, add=TRUE)