redist.dist.pop.overlap: Compare the Population Overlap Across Plans at the District...

In redist: Simulation Methods for Legislative Redistricting

Compare the Population Overlap Across Plans at the District Level

Description

This implements Crespin's 2005 measure of district continuity, as applied to the geographies represented by a plan, typically precincts or voting districts. This implementation assumes none of the precincts in plan_old or plan_new are split.

Usage

redist.dist.pop.overlap(plan_old, plan_new, total_pop, normalize_rows = TRUE)

Arguments

plan_old	The reference or original plan to compare against
plan_new	The new plan to compare to the reference plan
total_pop	The total population by precinct This can also take a redist_map object and will use the population in that object. If nothing is provided, it weights all entries in plan equally.
normalize_rows	Default TRUE. Normalize populations by row. If FALSE, normalizes by column. If NULL, does not normalize.

Value

matrix with length(unique(plan_old)) rows and length(unique(plan_new)) columns

References

"Using Geographic Information Systems to Measure District Change, 2000-02", Michael Crespin, Political Analysis (2005) 13(3): 253-260

Examples

set.seed(5)
data(iowa)
iowa_map <- redist_map(iowa, total_pop = pop, pop_tol = 0.01, ndists = 4)
plans <- redist_smc(iowa_map, 2)
plans_mat <- get_plans_matrix(plans)
ov <- redist.dist.pop.overlap(plans_mat[, 1], plans_mat[, 2], iowa_map)
round(ov, 2)

ov_col <- redist.dist.pop.overlap(plans_mat[, 1], plans_mat[, 2], iowa_map, normalize_rows = FALSE)
round(ov_col, 2)

ov_un_norm <- redist.dist.pop.overlap(plans_mat[, 1], plans_mat[, 2],
    iowa_map, normalize_rows = NULL)
round(ov_un_norm, 2)

iowa_map_5 <- iowa_map <- redist_map(iowa, total_pop = pop, pop_tol = 0.01, ndists = 5)
plan_5 <- get_plans_matrix(redist_smc(iowa_map_5, 1))
ov4_5 <- redist.dist.pop.overlap(plans_mat[, 1], plan_5, iowa_map)
round(ov4_5, 2)

redist documentation built on June 24, 2024, 9:10 a.m.