Compare displacement between two exploded layouts

Summarises how per-feature displacement changes between two layouts of the same input (e.g. different alpha_r/alpha_l/gamma choices or before/after collision refinement). Both layouts must be of the same class and cover the same input features in the same row order; this is verified by comparing the original geometries pairwise, so comparing two unrelated layouts of equal size is an error.

Usage

compare_layouts(before, after)

Arguments

before, after

exploded_map objects (or both grouped_exploded_map objects) to compare.

Value

A list with two elements:

• per_feature: data.frame with one row per feature and columns distance_before, distance_after, and delta (after minus before), in metres.

• summary: data.frame with one row per layout ("before", "after") and columns total, mean, and max displacement.

Examples

# \donttest{
sq <- function(xmin, ymin, size = 1) {
  sf::st_polygon(list(matrix(
    c(xmin, ymin, xmin + size, ymin, xmin + size, ymin + size,
      xmin, ymin + size, xmin, ymin),
    ncol = 2, byrow = TRUE
  )))
}
x <- sf::st_sf(
  id = c("a1", "a2", "b1", "b2"),
  region = c("A", "A", "B", "B"),
  geometry = sf::st_sfc(sq(0, 0), sq(2, 0), sq(10, 0), sq(12, 0), crs = 3857)
)
small <- explode_sf(x, region_col = "region", alpha_r = 10, alpha_l = 10,
                    plot = FALSE, quiet = TRUE)
big <- explode_sf(x, region_col = "region", alpha_r = 100, alpha_l = 100,
                  plot = FALSE, quiet = TRUE)
cmp <- compare_layouts(small, big)
cmp$summary
#>   layout total mean max
#> 1 before    40   10  20
#> 2  after   400  100 200
# }