Changing scale and color of a map

[Mdavidjolly]

I have ploted a grapht using the code below;

mapdata <- left_join(mapdata, data, by= "region")
mapdata <- mapdata %>% filter(!is.na(mapdata$UHCindex2017))
map1 <- ggplot(mapdata, aes(x = long, y = lat, group = group)) +
geom_polygon(aes(fill = indexchange), color = "yellow") +
theme_dark()
map1

I would like to change the color of the graph and also the scale.
How can I do this?

[jlacko]

Hard to tell without having your data...

But that is too easy answer to give, so in principle:

• for colors consider adjusting the scale_fill_* part of your ggplot call
• for zoom consider adjusting the coords_sf() part of your ggplot call; note that you can set both X and Y limits separately, with interesting interpretation of the special value of NA as "leave it as it stands"

So consider this piece of code as a baseline - it draws a dull default:

library(sf)
library(ggplot2)

shape <- st_read(system.file("shape/nc.shp", package="sf"))   # included with sf package

# default zoom, default colors
ggplot(data = shape,
       aes(fill = BIR74)) +
  geom_sf()

And now consider this, slightly adjusted, piece of code:

# zoom + colours from https://www.imdb.com/title/tt0362270/ - just for the heck of it...
ggplot(data = shape,
aes(fill = BIR74)) +
  geom_sf() +
  scale_fill_gradientn(colours = wesanderson::wes_palette("Zissou1", 100, type = "continuous")) + 
  coord_sf(xlim = c(-90, NA),
           ylim = c(NA, 40))

What it does differently is:

• it sets fill colors to a Wes Anderson palette - Zissou's Life Aquatic, because why not?
• it zooms the map out by extending the X coordinate westward to -90° and Y coordinate northward to 40°, leaving the east and south margins unchanged (again, for no particular reason other than just showing off...)