Create a Heat Map in R using ggplot2 with viridis Color Scale

ggplot2_heatmap_simple.R

# references:
# https://rud.is/b/2016/02/14/making-faceted-heatmaps-with-ggplot2/ 
# This is basically the TL;DR and it also uses a built-in dataset to foster reproducibility


library(ggplot2)
library(viridis)

gg <- ggplot(airquality, aes(x=Day, y=Month, fill=Temp))
gg <- gg + geom_tile(color='White', size=0.1)
gg <- gg + scale_fill_viridis(name="Temperature")
gg <- gg + coord_equal() + ggtitle("Sample Heat Map for Population")

gg