Create a hexagonal map as an sf object

hex_sf.R

if(!require("sf")){
  install.packages("sf")
  library("sf")
}

hex_sf <- function(x, y, radius = 1){
  stopifnot(length(y) == length(x) && 
              is.integer(x) && is.integer(y))
  center_x <- sqrt(3) * radius * x + 
    sqrt(3) / 2 * radius * y
  center_y <- 1.5 * radius * y
  hex_polygon <- function(center_x, center_y, radius){
    st_polygon(list(cbind(
      cos(pi/2 + pi/3 * c(0:5,0)) * radius + center_x,
      sin(pi/2 + pi/3 * c(0:5,0)) * radius + center_y)))
  }
  sfc <- st_sfc(Map(hex_polygon, center_x, center_y, radius))
  st_sf(data.frame(X=x, Y=y, hexCX = center_x, hexCY = center_y, 
                   geom=sfc))
}

sample_hex_map.R

if(!require("ggplot2")){
  install.packages("ggplot2")
  library("ggplot2")
}

x1 <- c(-1L,  0L, 0L, 1L, 1L, 2L, 2L, 2L)
y1 <- c(-1L, -1L, 0L, 1L, 2L, 1L, 2L, 3L)
hexmap1 <- hex_sf(x1, y1)

ggplot(hexmap1) + geom_sf() + 
  geom_text(aes(hexCX, hexCY, 
                label = paste(X, Y, sep=", ")))

sample_hex_map_result.png