## ----include = FALSE----------------------------------------------------------
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)

## ----setup, eval = FALSE, results = 'hide', message = FALSE, warning = FALSE----
# library(centr)
# library(sf)
# library(tidycensus)
# 
# NC_tracts <- get_decennial(
#   "tract",
#   state = "NC",
#   "P1_001N",
#   year = 2020,
#   geometry = TRUE
# )
# NC_counties <- st_read(system.file("shape/nc.shp", package = "sf"))

## ----include = FALSE----------------------------------------------------------
library(centr)
library(sf)

NC_tracts <- readRDS("files/nc_tracts.rds")
NC_counties <- st_read(system.file("shape/nc.shp", package = "sf"))

## -----------------------------------------------------------------------------
NC_tracts <- NC_tracts |>
  transform(GEOID_county = substring(GEOID, 1, 5)) |>
  subset(select = c(GEOID_county, value))

## ----error = TRUE-------------------------------------------------------------
try({
mean_center(NC_tracts, group = "GEOID_county", weight = "value")
})

## -----------------------------------------------------------------------------
NC_tracts <- subset(NC_tracts, !st_is_empty(NC_tracts))

## -----------------------------------------------------------------------------
NC_county_means <- mean_center(
  NC_tracts,
  group = "GEOID_county",
  weight = "value"
)
NC_county_means

## -----------------------------------------------------------------------------
plot(st_geometry(NC_counties))
plot(st_geometry(NC_county_means), pch = 20, cex = 0.5, col = "red", add = TRUE)

## -----------------------------------------------------------------------------
NC_tracts_proj <- st_transform(NC_tracts, crs = "EPSG:32119")

NC_county_medians <- NC_tracts_proj |>
  median_center(group = "GEOID_county", weight = "value")
NC_county_medians

## -----------------------------------------------------------------------------
NC_counties_proj <- st_transform(NC_counties, crs = "EPSG:32119")

plot(st_geometry(NC_counties_proj))
plot(
  st_geometry(NC_county_medians),
  pch = 20,
  cex = 0.5,
  col = "red",
  add = TRUE
)