routed_unit_cost: Field cost per sampled unit at a given sample size, from the...

In fieldopt: Area-Frame and Dual-Frame Survey Design under Real Field Cost

Field cost per sampled unit at a given sample size, from the routing

Description

Selects n units from the frame n_rep times, routes each sample from the depot, prices it with the cost model and returns the mean cost per sampled unit. This is the planning value of the cost of a primary unit (c1 in two_stage_allocation()) or of an area-frame unit (cost_a in dual_frame_allocation()); it depends on n because a larger sample is denser and cheaper to reach per unit.

Usage

routed_unit_cost(
  frame,
  depot,
  cost_model,
  n,
  size = NULL,
  strata = NULL,
  selection = c("lpm", "systematic", "srs"),
  replicates = 1,
  matrix = NULL,
  method = c("haversine", "euclidean", "osrm"),
  max_length = Inf,
  max_stops = Inf,
  n_rep = 10,
  iterations = 100,
  seed = 1
)

Arguments

frame	Data frame of units as in select_units(), including the depot row named in depot.
depot	Name of the depot unit in frame$unit.
cost_model	A field_cost_model().
n	Sample size (a number, or a vector named by stratum).
size	Optional size column for probability-proportional-to-size selection.
strata	Optional stratum column, passed to select_units().
selection	Selection method of select_units(): "lpm", "systematic" or "srs".
replicates	Replicates of a "systematic" selection.
matrix	Optional travel_matrix() of the frame (computed from the coordinates otherwise).
method	Distance method of travel_matrix() when matrix is NULL ("osrm" queries the road network once for the whole frame).
max_length, max_stops	Route limits passed to route_fieldwork().
n_rep	Replications per sample size.
iterations	GRASP iterations per routing.
seed	Seed.

Value

A one-row tibble: n, cost_per_unit, travel_per_unit, cost_mean, routes_mean, n_rep.

Examples

set.seed(1)
frame <- data.frame(
  unit = c("depot", paste0("s", 1:40)),
  x = c(5, runif(40, 0, 10)), y = c(5, runif(40, 0, 10))
)
model <- field_cost_model(
  per_travel = 2, per_unit = 30, per_interview = 10,
  interviews_per_unit = 4
)
routed_unit_cost(frame, "depot", model,
  n = 12, method = "euclidean", n_rep = 3,
  iterations = 20
)

fieldopt documentation built on Oct. 22, 2026, 1:07 a.m.