00a-hexagonal-grid-prep.md

Create hexagonal global grid

Ate Poorthuis 02/09/2019

Create hexagonal global grid

We start by reading in country-level data from Natural Earth. The end-goal is to create a global hexagonal grid with cells of 200km. Cells should be neatly clipped to the land boundaries.

countries <- read_sf(here("analysis/data/raw_data/ne_50m_admin_0_countries/")) %>% 
  st_transform(crs = "+proj=moll +lon_0=0 +x_0=0 +y_0=0 +ellps=WGS84 +datum=WGS84 +units=m +no_defs")
plot(st_geometry(countries))

hexagons <- countries %>% 
  st_buffer(400000) %>% 
  st_make_grid(cellsize = 200000, square = F) %>% 
  st_sf() %>% 
  rowid_to_column("hex")

hexagons_clipped <- countries %>% 
  st_buffer(100) %>% 
  st_intersection(hexagons) %>% 
  select(hex) %>% 
  group_by(hex) %>% 
  summarise()

## Warning: attribute variables are assumed to be spatially constant
## throughout all geometries

plot(st_geometry(hexagons_clipped))

The resulting grids are saved in analysis/data/derived_data.

st_write(hexagons_clipped, here("analysis/data/derived_data/global_hex_grid.geojson"), delete_dsn = T)

## Deleting source `/Users/ate/Documents/geographyoffashion/analysis/data/derived_data/global_hex_grid.geojson' using driver `GeoJSON'
## Writing layer `global_hex_grid' to data source `/Users/ate/Documents/geographyoffashion/analysis/data/derived_data/global_hex_grid.geojson' using driver `GeoJSON'
## features:       5643
## fields:         1
## geometry type:  Unknown (any)

saveRDS(hexagons_clipped, here("analysis/data/derived_data/global_hex_grid.rds"))