Find best route between 2 airports — find

find_route finds the quickest route between two airports, refuelling if necessary

Usage

find_route(
  ac,
  ap2,
  fat_map,
  avoid = NA,
  route_grid,
  cf_subsonic = NA,
  refuel = NA,
  refuel_h = 1,
  refuel_only_if = TRUE,
  refuel_topN = 1,
  max_circuity = 2,
  ap_loc,
  margin_km = 200,
  ...
)

Arguments

ac: One aircraft, as from make_aircraft
ap2: One airport pair, as from make_AP2
fat_map: sf::MULTIPOLYGON map of land, including buffer
avoid: sf::MULTIPOLYGON map of areas not to fly over
route_grid: GridLat routing grid as from make_route_grid
cf_subsonic: Further aircraft to use as comparator, default NA. (use is not recommended)
refuel: Airports available for refuelling, dataframe with APICAO, long, lat
refuel_h: Duration of refuelling stop, in hours
refuel_only_if: If TRUE (default) only test refuel options if necessary because the great circle distance is too far for the aircraft range
refuel_topN: Return the best N (default 1) refuelling options
max_circuity: Threshold for excluding refuelling stops (default 2.0)
ap_loc: Airport locations as from make_airports
margin_km: Great circle distance between airports must be less than aircraft range minus this operating margin (default 200km), to give a margin for arrival and departure.
...: Other parameters, passed to find_leg and thence to to make_route_envelope.

Value

Dataframe with details of the route

Details

This function finds the quickest route between two airports. A 'route' is made up of one or two 'legs' (airport to airport without intermediate stop). find_route makes one or more calls to find_leg as required.

It assumes that the routing grid, route_grid, has already been classified as land or sea using the map fat_map. The map is further used when converting the grid-based route to one of great circles segments.

Refuelling

If either necessary, because the great circle distance is greater than the aircraft range, or because refuel_only_if is FALSE, find_route searches through a list of refuelling airports and chooses the quickest one (or refuel_topN).

Circuitous refuelling is avoided, tested against total distance < max_circuity * great circle distance. This is separate to the limits placed on circuity of individual legs in find_leg.

If no refuel option is found, a message is displayed. The route with `NA` for `time_h` is returned.

Each refuelling stop costs refuel_h in addition to the time to descend to the airport and then to climb out again.

Examples

# need to load some of the built-in data
aircraft <- make_aircraft(warn = FALSE)
# get test datasets
NZ_buffer30 <- hm_get_test("buffer")
NZ_grid <- hm_get_test("grid")
airports <- make_airports(crs = sf::st_crs(NZ_buffer30))
#> Using default airport data: airportr::airport.

options("himach.verbosity" = 4) #for heavy reporting
# from Auckland to Christchurch
ap2 <- make_AP2("NZAA","NZCH",airports)
# on some CRAN machines even this takes too long, so not run
if (FALSE) { # \dontrun{
routes <- find_route(aircraft[4,],
                    ap2,
                    fat_map = NZ_buffer30,
                    route_grid = NZ_grid,
                    ap_loc = airports)
} # }