willgearty

gggeo_scale <- function(gg, fill = NULL, color = "black", alpha = 1, height = .05, size = 5, quat = FALSE, pos = "bottom", abbrv = TRUE, periods = NULL, neg = FALSE) {
  #This is a function to add a geologic time scale to a ggplot object.
  #gg: the ggplot object
  #fill: the fill color of the boxes; default are the colors from the Commission for the Geological Map of the World (CGMW);
  #   custom fill colors can be provided and will be recycled if necessary
  #   if a custom dataset is provided with periods without color and without fill, a greyscale will be used
  #color: the outline color of the boxes
  #alpha: transparency of the fill colors
  #height: the proportional height of the plot to use for the scale 
  #size: the size of the text in the scale