2.5 Basic map mapping

world_asia = world[world$continent == "Asia", ]
asia = st_union(world_asia)
plot(world["pop"], reset = FALSE)
plot(asia, add = TRUE, col = "red")

plot concept is adding layer. It is good for quick vizualisation.

-> for more advanced mapping: tmap

But base plot is still a powerful tool:

plot(world["continent"], reset = FALSE)
cex = sqrt(world$pop) / 10000
world_cents = st_centroid(world, of_largest = TRUE)

## Warning: st_centroid assumes attributes are constant over geometries

plot(st_geometry(world_cents), add = TRUE, cex = cex)

• expandBB is quite good for simple context map:

india = world[world$name_long == "India", ] # TODO discuss the subset
plot(st_geometry(india), expandBB = c(0, 0.2, 0.1, 1), col = "gray", lwd = 3)
plot(st_geometry(world_asia), add = TRUE)