Add county and municipality fields by joining on a shared key

The non-spatial counterpart to add_muni_from_shapes(). Instead of a point-in-polygon join, it merges geography attributes from a boundary layer onto geocoded records by a shared key column (for example a ZIP, FIPS, GEOID, or local region code that both tables carry). Use it when a spatial join is not the right criterion - the records may lack coordinates, or the authoritative geography is keyed by a code rather than a polygon footprint.

Usage

add_muni_from_key(
  data,
  muni_shapes,
  data_key,
  shp_key,
  county_col = NULL,
  muni_col = NULL,
  key_col = NULL
)

Arguments

data

A data frame of geocoded records carrying data_key.

muni_shapes

An sf polygon (or attribute) layer carrying shp_key and the geography attributes to attach.

data_key

Name (string) of the join-key column in data.

shp_key

Name (string) of the join-key column in muni_shapes.

county_col, muni_col

Optional explicit county / locality column names in muni_shapes. Empty strings are treated as unset.

key_col

Optional municipal key column in muni_shapes.

Value

data with County, Municipality, Muni Key, muni_join_key, county_code, county_fips, municipality_code, municipality_geoid, municipality_name_standard, municipality_type, muni_match_status, and the generic location_county / location_locality / geography_match_status audit fields.

Details

Output columns match add_muni_from_shapes() exactly, so the two join paths are interchangeable downstream: County, Municipality, Muni Key, muni_join_key, the stable code/identifier fields, location_county, location_locality, geography_match_status, and muni_match_status. Stable code fields (county_code, municipality_code, municipality_geoid, etc.) are auto-detected from common boundary schemas; county_fips is synthesised from a state FIPS plus county code when not supplied directly, and Muni Key falls back to County::Municipality when no official identifier exists.

See also

add_muni_from_shapes() for the spatial (point-in-polygon) join.