Locate Anchorage, AK using the albersusa package for R

albers_anchorage.R

# find where to locate Anchorage, AK using the albersusa package

# dependencies
library(albersusa)   # composite projection
library(dplyr)       # data wrangling
library(ggplot2)     # mapping
library(mapview)     # preview
library(sf)          # spatial data

# load composite map
us <- usa_composite("longlat")

# convert to sf
us <- st_as_sf(us)

# preview
# the trick is to use the {mapview} package and hover over the object from {albersusa} 
# so you can see the longitude and latitude of anchorage not where it is but in Baja California... 
# it's in the upper left corner of the {mapview} window
mapview(us)

# create new sf object
anchorage <- tibble(
  name = c("Anchorage"),
  x = c(-111.49443),
  y = c(25.84486)
)

anchorage <- st_as_sf(anchorage, coords = c("x", "y"), crs = 4326)

# convert to albers
albers <- "+proj=aea +lat_1=20 +lat_2=60 +lat_0=40 +lon_0=-96 +x_0=0 +y_0=0 +datum=NAD83 +units=m +no_defs"
us <- st_transform(us, crs = albers)
anchorage <- st_transform(anchorage, crs = albers)

# test map
ggplot() +
  geom_sf(data = us) +
  geom_sf(data = anchorage, color = "red", size = 4)