Overview

How to color a Raster Map with R.

# Install and load necessary packages
# install.packages(c("ggplot2", "raster"))
library(tidyverse)
library(raster)
library(rasterVis)

https://stackoverflow.com/questions/33359284/r-plot-background-map-from-geotiff-with-ggplot2

alaska <- "data/SR_50M_alaska_nad.tif"
alaska_raster <- raster(alaska)
ctab <- rep(RColorBrewer::brewer.pal(n = 8, name = "RdBu"),200)
colortable(alaska_raster) <- ctab
gplot(alaska_raster, maxpixels = 10e5) +
  geom_tile(aes(fill = factor(value))) +
  scale_fill_manual(values = ctab,guide = "none") +
  coord_equal()+
  ggthemes::theme_map()

alaska <- "data/SR_50M_alaska_nad.tif"
alaska_raster <- raster(alaska)

alaska_df <- as.data.frame(rasterToPoints(alaska_raster))
val <- unique(alaska_df$SR_50M_alaska_nad)

Fonts:

library(sysfonts)
font_add_google("Raleway","Raleway")
showtext::showtext_auto()

Colors:

colors <- c("#001F3F","#008080","#00BCD4","#4CAF50",
            "#8BC34A","#FFD700")

Map:

map <- gplot(alaska_raster, maxpixels = 10e5) +
  geom_tile(aes(fill = value)) +
  scale_fill_gradientn(colors=rev(colors))+
  coord_equal()+
  labs(title="Alaska",
       subtile="#30DayMapChallenge 2023 Day 21 Raster",
       caption="Colors indicate the high and low level of elevation in Alaska\nDataSource: QGis Raster Sample Data | Map: @fgazzelloni",fill="Elevation")+
  ggthemes::theme_map()+
  theme(text=element_text(family="Raleway",color="#f6f7f9",
                          size=40),
        panel.grid = element_line(color="#f6f7f9"),
        plot.title = element_text(hjust=0.5,vjust=-0.1,
                                  size=120,
                                  face="bold"),
        plot.caption = element_text(lineheight = 0.4),
        legend.position = "bottom",
        legend.background = element_blank(),
        legend.text = element_text(color="#f6f7f9",
                                   lineheight = 0.4),
        plot.background = element_rect(color="grey50",fill="grey50"),
        panel.background = element_rect(color="grey50",fill="grey50"))
showtext::showtext_end()

ggsave(map,"day21_raster2.png",
       dpi=320,
       bg="grey50")