ContourLines to SpatialPolygons

contoursToSP01.r

#required packages:
require(raster)
require(maptools)
require(Grid2Polygons)

#define breaks for the contour lines:
breaks <- seq(80, 200, length.out = 15)

#first convert the volcano matrix to a raster
poly_volcano <- raster(volcano)

#convert the raster to contour lines
poly_volcano <- rasterToContour(poly_volcano, levels = breaks)

#convert the SpatialLines into a PolySet
poly_volcano <- SpatialLines2PolySet(poly_volcano)

#convert the Polyset into SpatialPolygons
poly_volcano <- PolySet2SpatialPolygons(poly_volcano)

#plot the resulting SpatialPolygons
png("volcano01.png", 200, 200)
par(oma = c(0,0,0,0), mar = c(0,0,0,0))
plot(poly_volcano, col = terrain.colors(length(poly_volcano)))
dev.off()