Subsets a shp object along with its adjacency. Useful for running smaller analyses on pairs of districts. Provide population, ndists, pop_tol, and sub_ndists to get proper population parity constraints on subsets.

redist.subset(shp, adj, keep_rows, total_pop, ndists, pop_tol, sub_ndists)

Arguments

shp

An sf object

adj

A zero-indexed adjacency list. Created with redist.adjacency if not supplied.

keep_rows

row numbers of precincts to keep. Random submap selected if not supplied.

total_pop

numeric vector with one entry for the population of each precinct.

ndists

integer, number of districts in whole map

pop_tol

The strength of the hard population constraint.

sub_ndists

integer, number of districts in subset map

Value

a list containing the following components:

shp

The subsetted shp object

adj

The subsetted adjacency list for shp

keep_rows

The indices of the rows kept.

sub_ndists

The number of districts in the subset.

sub_pop_tol

The new parity constraint for a subset.