ggplot(map_and_data)+
  geom_sf(aes(fill=SPEI))+
  facet_wrap(~ Year)+
scale_fill_gradient(low = "yellow", high = "blue")+
  theme_bw()+
  theme(axis.text = element_text(size=14), plot.subtitle = element_text(size = 20))+
  theme(legend.position = "bottom", legend.title = element_blank(), legend.key.width = unit(3,"cm"), legend.text = element_text(size=18))