Join User Data to a jpmap Boundary Object

jp_map_join() attaches columns from a user data frame to an sf object returned by jp_map(). It is designed for common Japan-map keys, including pref_code, jis_code, and municipality_code, and keeps leading zeroes from getting in the user's way.

Usage

jp_map_join(
  map,
  data,
  by = NULL,
  values = NULL,
  unmatched = c("warning", "error", "ignore"),
  multiple = c("error", "first")
)

Arguments

map: An sf object returned by jp_map().
data: A data frame with one row per region to join.
by: Join column. If NULL, jpmap guesses from common columns such as jis_code, municipality_code, pref_code, prefecture, prefecture_ja, municipality, and municipality_ja. To join columns with different names, use a named character vector such as c("pref_code" = "code"), where the name is the map column and the value is the data column.
values: Optional column expected to exist after joining. This is useful when checking data before passing it to a plotting function.
unmatched: What to do when user data rows do not match the map, or map regions do not receive a data row. One of "warning", "error", or "ignore".
multiple: What to do when data has duplicate join keys. One of "error" or "first".

Value

An sf object with non-geometry columns from data joined to map.

Examples

if (requireNamespace("dplyr", quietly = TRUE) &&
    nrow(available_jpmap_data()) > 0) {
  data("jp_prefecture_gdp")

  gdp <- jp_prefecture_gdp |>
    dplyr::select(pref_code, gdp_per_capita_jpy)

  joined <- jp_map("prefecture") |>
    jp_map_join(gdp, by = "pref_code")

  "gdp_per_capita_jpy" %in% names(joined)
}
#> [1] TRUE