split_precinct: Split a Precinct

In geomander: Geographic Tools for Studying Gerrymandering

Split a Precinct

Description

States often split a precinct when they create districts but rarely provide the geography for the split precinct. This allows you to split a precinct using a lower geography, typically blocks.

Usage

split_precinct(lower, precinct, split_by, lower_wt, split_by_id, epsg = 3857)

Arguments

lower	The lower geography that makes up the precinct, this is often a block level geography.
precinct	The single precinct that you would like to split.
split_by	The upper geography that you want to split precinct by
lower_wt	Optional. Numeric weights to give to each precinct, typically VAP or population.
split_by_id	Optional. A string that names a column in split_by that identifies each observation in split_by
epsg	numeric EPSG code to planarize to. Default is 3857.

Value

sf data frame with precinct split

Examples

library(sf)
data(checkerboard)
low <- checkerboard %>% dplyr::slice(1:3, 9:11)
prec <- checkerboard %>%
  dplyr::slice(1:3) %>%
  dplyr::summarize(geometry = sf::st_union(geometry))
dists <- checkerboard %>%
  dplyr::slice(1:3, 9:11) %>%
  dplyr::mutate(dist = c(1, 2, 2, 1, 3, 3)) %>%
  dplyr::group_by(dist) %>%
  dplyr::summarize(geometry = sf::st_union(geometry))

split_precinct(low, prec, dists, split_by_id = 'dist')

geomander documentation built on April 16, 2023, 5:18 p.m.