This function produces a map with geographic regions defined by polygons. It is essentially the same function as
polys.plot() in mgcv but with added arguments zlim and rev.col and a wider set of choices for
scheme.
polys.map(lm, z, scheme = "gray", lab = "", zlim, rev.col = TRUE, ...)lm. "heat", "terrain", "topo", "cm" and "gray", indicating how to fill
the polygons in accordance with the value of z.pretty(z) otherwise the range provided will be used.FALSE then coloring scheme is not reversed.See help file of polys.plot in mgcv.