Created
January 20, 2021 10:37
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Creates a gif of the world in different map projections
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library(tidyverse) | |
library(sf) | |
library(spData) | |
library(gganimate) | |
data(world) | |
# see also: https://proj.org/operations/projections/index.html | |
projs <- list( | |
"Mercator" = "+proj=merc", | |
"WGS 84" = "+proj=longlat", | |
"Robinson" = "+proj=robin", | |
"Compact Miller" = "+proj=comill", | |
"Eckert I" = "+proj=eck1", | |
"Eckert II" = "+proj=eck2", | |
"Eckert III" = "+proj=eck3", | |
"Eckert IV" = "+proj=eck4", | |
"Mollweide" = "+proj=moll", | |
"Azimuth Equidistant" = "+proj=aeqd", | |
"Lambert Equal Area" = "+proj=laea", | |
"Adams World in a Square 2" = "+proj=adams_ws2", | |
"Sinusoidal (Sanson-Flamsteed)" = "+proj=sinu", | |
"Interrupted Goode Homolosine" = "+proj=igh" | |
) | |
dd <- map_dfr(projs, function(p) { | |
d <- world %>% | |
select(iso_a2, name_long, continent, geom) %>% | |
mutate(projection = p, L1 = 1:n()) %>% | |
st_transform(p) | |
dd <- left_join( | |
st_coordinates(d) %>% as_tibble(), | |
d %>% as_tibble() %>% select(-geom), | |
by = "L1" | |
) | |
res <- dd %>% | |
select(x = X, y = Y, everything()) %>% | |
mutate(id = paste0(L1, L2, L3)) %>% | |
mutate(x_orig = x, y_orig = y, | |
x = (x - min(x)) / (max(x) - min(x)), | |
y = (y - min(y)) / (max(y) - min(y))) | |
res | |
}) %>% | |
mutate(projection = factor(projection, levels = unlist(projs))) | |
anim <- ggplot(dd, aes(x = x, y = y, group = id)) + | |
geom_polygon(fill = "black") + | |
transition_states(projection) + | |
ease_aes("cubic-in-out") + | |
labs(title = "The World in '{names(projs)[projs == closest_state]}' Projektion", | |
subtitle = "Projection: '{closest_state}'") + | |
theme_minimal() + | |
theme(axis.title=element_blank(), | |
axis.text=element_blank(), | |
axis.ticks=element_blank(), | |
panel.grid=element_blank(), | |
plot.background=element_rect(fill = "white")) | |
anim_save("images/projections.gif", anim, res = 200, width = 1000, height = 1000) |
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Thanks. I'll give it a go.