Estimate Values Down to a Finer Geography — geo_estimate

Split values observed on a larger geography across a smaller geography after first matching each row of to to a row of from. This is commonly used to distribute precinct-level election totals to blocks.

Usage

geo_estimate_down(from, to, wts, value, method = "center", epsg = 3857)

Arguments

from: Larger geography level containing the observed values.
to: Smaller geography level to estimate onto.
wts: Numeric vector of length nrow(to). Used to allocate each matched value across rows of to. Defaults to 1, which splits evenly within each matched group.
value: Numeric vector of length nrow(from) containing the values to split downward. Defaults to 1.
method: Matching method passed to geo_match().
epsg: numeric EPSG code to planarize to. Default is 3857.

Value

numeric vector of length nrow(to) with estimated values

Details

If all weights for a matched group are zero, the function falls back to equal allocation within that group. Rows in to that do not match any row of from receive 0.

Examples

library(dplyr)
set.seed(1)
data(checkerboard)
counties <- checkerboard |>
  group_by(id <= 32) |>
  summarize(geometry = sf::st_union(geometry)) |>
  mutate(pop = c(100, 200))
geo_estimate_down(from = counties, to = checkerboard, value = counties$pop)
#> Warning: Planarizing skipped. `x` missing CRS.
#> Warning: Planarizing skipped. `x` missing CRS.
#>  [1] 6.250 6.250 6.250 6.250 6.250 6.250 6.250 6.250 6.250 6.250 6.250 6.250
#> [13] 6.250 6.250 6.250 6.250 6.250 6.250 6.250 6.250 6.250 6.250 6.250 6.250
#> [25] 6.250 6.250 6.250 6.250 6.250 6.250 6.250 6.250 3.125 3.125 3.125 3.125
#> [37] 3.125 3.125 3.125 3.125 3.125 3.125 3.125 3.125 3.125 3.125 3.125 3.125
#> [49] 3.125 3.125 3.125 3.125 3.125 3.125 3.125 3.125 3.125 3.125 3.125 3.125
#> [61] 3.125 3.125 3.125 3.125