Keep customized colors with geom_polygon()

Question

I have plotted a map of France with customized colors with map():

map(database="france", fill=TRUE, col=color)

Results:

(don't mind the two errors)

and then I want to put this map with a projection of Lambert using ggplot2 package :

head(fortify(carte_france))
ggplot(map('france'), aes(long, lat, group = group)) +
  geom_polygon(col = 1) + 
  coord_map(projection = "lambert",
            parameters = c(lat0 = 41.366005 , lat1 = 51.097523))

However it gives me this :

I know that the dark colours comes from the arg fill from geom_polygon(), but is there a way to tell the function geom_polygon() to not use the argument fill or to keep the colors I have put before?

Vector of colours:

color <- c("yellowgreen", "yellowgreen", "yellowgreen", "yellowgreen", 
"gold1", "sienna3", "yellowgreen", "yellowgreen", "sienna3", 
"gold1", "gold1", "gold1", "sienna3", "sienna3", "gold1", "dodgerblue2", 
"dodgerblue2", "dodgerblue2", "gold1", "dodgerblue2", "sienna3", 
"dodgerblue2", "burlywood2", "dodgerblue2", "palevioletred4", 
"dodgerblue2", "palevioletred4", "dodgerblue2", "palevioletred4", 
"palevioletred4", "gold1", "palevioletred4", "gold1", "darkorchid4", 
"gold1", "darkorchid4", "palevioletred4", "green4", "cyan4", 
"gold1", "palevioletred4", "burlywood2", "green4", "green4", 
"cyan4", "darkorchid4", "green4", "burlywood2", "palevioletred4", 
"burlywood2", "green4", "green4", "palevioletred4", "palevioletred4", 
"palevioletred4", "green4", "burlywood2", "olivedrab2", "green4", 
"olivedrab2", "darkorchid4", "darkorchid4", "cyan4", "darkorchid4", 
"cyan4", "cyan4", "olivedrab2", "olivedrab2", "olivedrab2", "cyan4", 
"cyan4", "olivedrab2", "cyan4", "olivedrab2", "olivedrab2", "cyan4", 
"cyan4", "olivedrab2", "olivedrab2", "olivedrab2", "cyan4", "cyan4", 
"cyan4", "cyan4", "orange2", "orangered1", "orangered1", "orangered1", 
"olivedrab2", "orange2", "olivedrab2", "orangered1", "orange2", 
"orangered1", "orange2", "orange2", "orangered1", "orangered1", 
"orangered1", "orange2", "orangered1", "orange2", "orangered1", 
"olivedrab2", "orangered1", "orangered1", "orangered1", "orangered1", 
"orange2", "orange2", "orange2", "chartreuse3", "orangered1", 
"chartreuse3")

Answer 1

The trick to get the same colors in the ggplot is that you have to make a new vector repeating your color vector to reach the same length as the number of rows of the mapFrance object.

Try the reproducible and commented step-by-step code:

# Load libraries
library("maps")
library("ggplot2")

# Colors
color <- c("yellowgreen", "yellowgreen", "yellowgreen", "yellowgreen", 
           "gold1", "sienna3", "yellowgreen", "yellowgreen", "sienna3", 
           "gold1", "gold1", "gold1", "sienna3", "sienna3", "gold1", "dodgerblue2", 
           "dodgerblue2", "dodgerblue2", "gold1", "dodgerblue2", "sienna3", 
           "dodgerblue2", "burlywood2", "dodgerblue2", "palevioletred4", 
           "dodgerblue2", "palevioletred4", "dodgerblue2", "palevioletred4", 
           "palevioletred4", "gold1", "palevioletred4", "gold1", "darkorchid4", 
           "gold1", "darkorchid4", "palevioletred4", "green4", "cyan4", 
           "gold1", "palevioletred4", "burlywood2", "green4", "green4", 
           "cyan4", "darkorchid4", "green4", "burlywood2", "palevioletred4", 
           "burlywood2", "green4", "green4", "palevioletred4", "palevioletred4", 
           "palevioletred4", "green4", "burlywood2", "olivedrab2", "green4", 
           "olivedrab2", "darkorchid4", "darkorchid4", "cyan4", "darkorchid4", 
           "cyan4", "cyan4", "olivedrab2", "olivedrab2", "olivedrab2", "cyan4", 
           "cyan4", "olivedrab2", "cyan4", "olivedrab2", "olivedrab2", "cyan4", 
           "cyan4", "olivedrab2", "olivedrab2", "olivedrab2", "cyan4", "cyan4", 
           "cyan4", "cyan4", "orange2", "orangered1", "orangered1", "orangered1", 
           "olivedrab2", "orange2", "olivedrab2", "orangered1", "orange2", 
           "orangered1", "orange2", "orange2", "orangered1", "orangered1", 
           "orangered1", "orange2", "orangered1", "orange2", "orangered1", 
           "olivedrab2", "orangered1", "orangered1", "orangered1", "orangered1", 
           "orange2", "orange2", "orange2", "chartreuse3", "orangered1", 
           "chartreuse3")

# Make map
mapFrance <- map(database = "france", fill = TRUE, col = color)

• simple plot map

# Make gg object
gg <- ggplot(data = mapFrance)

# Make auxilliary data.frame
values <- data.frame("group" = factor(1:length(mapFrance$names)), "color" = color)

# Add color data to gg object by merging
gg$data <- merge(gg$data, values, by = c("group"))

# Plot gg object
gg + 
  geom_polygon(aes(x = long, y = lat, group = group),  fill = gg$data$color, colour = 1) + 
  coord_map(projection = "lambert", parameters = c(lat0 = 41.366005 , lat1 = 51.097523))

• ggplot2 map

Answer 2

The easiest way is to use scale_fill_identity in ggplot2:

library("ggplot2")
library("maps")
library("dplyr")

# create data frame and merge predefined colors in vector `color`
map_fr <- map_data("france") %>%
          left_join(data.frame(group = seq_along(color), color = color),
                    by = "group")

p <- ggplot(data = map_fr) +
     geom_polygon(aes(x = long, y = lat, group = group, fill = color),
                  colour = "black") +
     coord_map(projection = "lambert",
               parameters = c(lat0 = 41.366005 , lat1 = 51.097523)) +
     scale_fill_identity()

print(p)