Changing label colors with rGridMap

label_colors.R

devtools::install_github('arvi1000/rGridMap')
library(rGridMap)
library(ggplot2)

# a data.frame of states with random categorical value
set.seed(123)
my_dat <- data.frame(state.abb = c(state.abb, 'DC'), # don't forget DC!
                     value=sample(LETTERS[1:5], 51, replace=T))

plotGridMap(my_dat, fill_var = 'value',
            # this turns labels white
            label_color = 'white') +
  scale_fill_brewer(type='qual', palette = 2) +
  labs(title = 'States by Category', fill = 'Category',
       subtitle = 'black background, white state labels') +
  # this is to make background black
  theme(rect = element_rect(fill='black'),
        text = element_text(color='white'),
        legend.key= element_blank())