South Up Equal Earth Projection in R

Yup - I'm still banging on about this! This time, in R

Result

The colours are wrong, and the labels need adjustment - but not bad for a few lines of code!

Code

 Rlibrary(tidyverse)

library(rnaturalearth)

library(rnaturalearthdata)

library(sf)



centre <- 160 # NZ mostly centred, prevents Africa and South America wrapping.

projection <- "eqearth" # Other good projections are wag1 wag7 eck4 eqearth



crs_string <- paste( "+proj=", projection, " +lon_0=", centre, " +axis=wsu", sep="") # WSU puts South up



target_crs <- st_crs(  crs_string  )



worldrn <- ne_countries( scale = "medium", returnclass = "sf" ) %>%

   st_make_valid()



offset <- 180 - centre



#  Recalculate the polygons

polygon <- st_polygon( x = list(rbind(

                                 c(-0.0001 - offset, 90),

                                 c(0 - offset, 90),

                                 c(0 - offset, -90),

                                 c(-0.0001 - offset, -90),

                                 c(-0.0001 - offset, 90)

))) %>%

   st_sfc() %>%

   st_set_crs(4326)





# modify world dataset to remove overlapping portions with world's polygons

world2 <- worldrn %>% st_difference(polygon)



# Transform

world3 <- world2 %>% st_transform(crs = target_crs)

ggplot(data = world3, aes(group = admin)) +

   #geom_sf( fill = "red" ) +

   geom_sf( fill = world3$mapcolor13, lwd = 0 ) + # remove borders

   geom_sf_label( aes( label = name_long ), label.size = 0, fill = NA, size = 1 ) + 

   theme( panel.grid.major = element_line( color = gray(.5), linetype = "dashed", size = 0.5 ), 

      panel.background = element_rect( fill = "#A7C7E7"))



#  Uncomment to save the map

#ggsave("map.png", width = 32, height = 18, units = "cm")

Further Reading

• https://gis.stackexchange.com/a/287094/129854
• https://r-spatial.org/r/2018/10/25/ggplot2-sf.html
• https://www.jasondavies.com/maps/raster/
• https://stackoverflow.com/questions/68278789/how-to-rotate-world-map-using-mollweide-projection-with-sf-rnaturalearth-ggplot