comp_x_sym {redistmetrics}

Calculate X Symmetry Compactness

Description

X symmetry is the overlapping area of a shape and its projection over the x-axis.

Usage

comp_x_sym(plans, shp, epsg = 3857, ncores = 1)

Arguments

plans

A redist_plans object or plans_matrix where each row indicates a district assignment and each column is a plan.

shp

A redist_map object, tibble, or data frame with an sf geometry column.

epsg

Numeric EPSG code to use to project the shapefile, if needed. Default is 3857.

ncores

Integer number of cores to use. Default is 1.

Value

A numeric vector. Can be shaped into a district-by-plan matrix.

References

Aaron Kaufman, Gary King, and Mayya Komisarchik. 2021. How to Measure Legislative District Compactness If You Only Know it When You See It. American Journal of Political Science. 65, 3. Pp. 533-550.

Examples

#' data(nh)
data(nh_m)
# For a single plan:
comp_x_sym(plans = nh$r_2020, shp = nh)

# Or many plans:

# slower, beware!
comp_x_sym(plans = nh_m[, 3:5], shp = nh)