nearestPump: Compute shortest distances or paths to selected pumps.

In cholera: Amend, Augment and Aid Analysis of John Snow's Cholera Map

Compute shortest distances or paths to selected pumps.

Description

Compute shortest distances or paths to selected pumps.

Usage

nearestPump(pump.select = NULL, metric = "walking", vestry = FALSE,
  weighted = TRUE, case.set = "observed", distance.unit = "meter",
  time.unit = "second", walking.speed = 5, multi.core = TRUE,
  dev.mode = FALSE)

Arguments

pump.select	Numeric. Pump candidates to consider. Default is NULL: all pumps are used. Otherwise, selection by a vector of numeric IDs: 1 to 13 for pumps; 1 to 14 for pumps.vestry. Negative selection allowed.
metric	Character. "euclidean" or "walking".
vestry	Logical. TRUE uses the 14 pumps from the Vestry Report. FALSE uses the 13 in the original map.
weighted	Logical. TRUE computes shortest path in terms of road length. FALSE computes shortest path in terms of the number of nodes.
case.set	Character. "observed", "expected", or "snow".
distance.unit	Character. Unit of distance: "meter", "yard" or "native". "native" returns the map's native scale. Meaningful only when "weighted" is TRUE. See vignette("roads") for information on unit distances.
time.unit	Character. "hour", "minute", or "second".
walking.speed	Numeric. Walking speed in km/hr.
multi.core	Logical or Numeric. TRUE uses parallel::detectCores(). FALSE uses one, single core. You can also specify the number logical cores. See vignette("Parallelization") for details.
dev.mode	Logical. Development mode uses parallel::parLapply().

Value

An R data frame or list of 'igraph' path nodes.

Note

Time is computed using distanceTime().

cholera documentation built on March 7, 2023, 5:31 p.m.