library(metR)
library(ggplot2)
v <- reshape2::melt(volcano)
g <- ggplot(v, aes(Var1, Var2)) +
geom_contour(aes(z = value))
g + geom_text_contour(aes(z = value))
#> Warning in as.numeric(group[1]) %in% rot.groups: NAs introduced by coercion
#> Warning in as.numeric(group[1]) %in% rot.groups: NAs introduced by coercion
#> Warning in as.numeric(group[1]) %in% rot.groups: NAs introduced by coercion
#> Warning in as.numeric(group[1]) %in% rot.groups: NAs introduced by coercion
#> Warning in as.numeric(group[1]) %in% rot.groups: NAs introduced by coercion
#> Warning in as.numeric(group[1]) %in% rot.groups: NAs introduced by coercion
#> Warning in as.numeric(group[1]) %in% rot.groups: NAs introduced by coercion
#> Warning in as.numeric(group[1]) %in% rot.groups: NAs introduced by coercion
#> Warning in as.numeric(group[1]) %in% rot.groups: NAs introduced by coercion
#> Warning in as.numeric(group[1]) %in% rot.groups: NAs introduced by coercion
#> Warning in as.numeric(group[1]) %in% rot.groups: NAs introduced by coercion
#> Warning in as.numeric(group[1]) %in% rot.groups: NAs introduced by coercion
#> Warning in as.numeric(group[1]) %in% rot.groups: NAs introduced by coercion
#> Warning in as.numeric(group[1]) %in% rot.groups: NAs introduced by coercion
#> Warning in as.numeric(group[1]) %in% rot.groups: NAs introduced by coercion
#> Warning in as.numeric(group[1]) %in% rot.groups: NAs introduced by coercion
#> Warning in as.numeric(group[1]) %in% rot.groups: NAs introduced by coercion
#> Warning in as.numeric(group[1]) %in% rot.groups: NAs introduced by coercion
#> Warning in as.numeric(group[1]) %in% rot.groups: NAs introduced by coercion
#> Warning in as.numeric(group[1]) %in% rot.groups: NAs introduced by coercion
Created on 2020-10-08 by the reprex package (v0.3.0)