Raster with heaxgons

hexagon.R

library(geodata)
library(giscoR)
library(tidyterra)
library(tidyverse)
library(terra)
library(sf)

folder <- ifelse(dir.exists("~/R/mapslib/misc"),
  "~/R/mapslib/misc",
  tempdir()
)


tmin <- worldclim_country("DEU", "tmin", path = folder) %>%
  select(11)

names(tmin) <- "tmin"
plot(tmin)

library(giscoR)

cntry <- gisco_get_countries(country = "Germany", epsg = 3035)


# Transform crs

tmin2 <- project(tmin, pull_crs(cntry))
plot(tmin2)

# Create hexbins
adjustarea <- sqrt(2 * 100000 * 1000 / sqrt(3))

hex <- st_make_grid(cntry,
  square = FALSE, flat_topped = TRUE,
  cellsize = adjustarea
)

units::set_units(st_area(hex[1]), "km^2")

hex <- st_sf(id = seq_len(length(hex)), geom = hex)
# Cut by centroid
cents <- st_centroid(hex, of_largest_polygon = TRUE)
ids <- st_filter(cents, cntry)

# And select
hex_end <- hex %>% inner_join(ids %>% st_drop_geometry())



# Rasterize
hex_end$min <- exactextractr::exact_extract(tmin2, hex_end, "mean")

range(hex_end$min)

ggplot(hex_end) +
  geom_sf(aes(fill = min)) +
  scale_fill_whitebox_c(palette = "deep", direction = -1,
                        breaks = seq(-4, 6, 1)
                        ) +
  guides(fill = guide_legend(
    title = "   ºC.",
    direction = "horizontal",
    nrow = 1,
    keywidth = 1.5,
    keyheight = 0.5,
    label.position = "bottom",
    title.position = "right"
  )) +
  theme_minimal() +
  theme(
    # plot.background = element_rect("grey99", colour = NA),
    plot.margin = margin(20, 20, 20, 20),
    plot.title = element_text(face = "bold"),
    plot.subtitle = element_text(
      margin = margin(b = 10)
    ),
    legend.position = "bottom",
    legend.key = element_rect(fill = "red", colour = NA, linewidth = 0),
    legend.spacing.x = unit(0, "pt")
  ) +
  labs(
    title = "Winter is coming to Germany",
    subtitle = "Avg. Minimum Temperature in November (25 km2 cell).",
    caption = "Source: WordClim"
  )

ggsave("deu.png", scale = 1.5, bg = "white")
knitr::plot_crop("deu.png")