Attach multiple Census geography levels to geocoded points

Enriches geocoded records with one or more Census TIGER/Line geography levels in a single call, by point-in-polygon assignment. Where add_county_muni() answers "which county and municipality", this answers "which tract, block group, ZCTA, congressional district, state legislative district, or school district" - the analysis and policy geographies that dashboards and grant reporting often need. Each requested level adds two columns: <level>_geoid (the Census GEOID) and <level>_name (the layer's name field, NA where the layer has none, e.g. ZCTAs).

Usage

add_census_geographies(
  data,
  state,
  levels = "tract",
  county = NULL,
  year = NULL,
  cb = TRUE,
  ...
)

Arguments

data: A geocoded data frame with latitude and longitude columns.
state: Two-letter state abbreviation or FIPS code (passed to tigris). ZCTAs are national, so state is ignored for the "zcta" level.
levels: Character vector of geography levels to attach. Any of "tract", "block_group", "zcta", "county", "place", "county_subdivision", "congressional_district", "state_legislative_district_upper", "state_legislative_district_lower", "school_district" (unified). Defaults to "tract".
county: Optional county filter (name or FIPS) for the levels that accept one ("tract", "block_group", "county_subdivision").
year: Vintage year for the boundary files. NULL uses the tigris default.
cb: If TRUE (default), use the smaller cartographic boundary files.
...: Passed through to the underlying tigris download functions.

Value

data with, for each requested level, a <level>_geoid and <level>_name column. Rows without usable coordinates get NA.

Details

The geography step only needs latitude/longitude; it does not touch the address columns. Downloads use tigris and therefore need network access.

Examples

if (interactive()) {
  enriched <- add_census_geographies(
    geocoded, state = "NJ",
    levels = c("tract", "congressional_district", "school_district")
  )
}