otp_get_isochrone: Returns one or more travel time isochrones (OTPv1 only)
In otpr: An R Wrapper for the 'OpenTripPlanner' REST API

Description Usage Arguments Value Examples

Returns one or more travel time isochrones in either GeoJSON format or as an sf object. Only works correctly for walk and/or transit modes - a limitation of OTP. Isochrones can be generated either from a location or to a location.

otp_get_isochrone(
  otpcon,
  location,
  fromLocation = TRUE,
  format = "JSON",
  mode = "TRANSIT",
  date = format(Sys.Date(), "%m-%d-%Y"),
  time = format(Sys.time(), "%H:%M:%S"),
  cutoffs,
  batch = TRUE,
  arriveBy = FALSE,
  maxWalkDistance = NULL,
  walkReluctance = 2,
  waitReluctance = 1,
  transferPenalty = 0,
  minTransferTime = 0,
  extra.params = list()
)

`otpcon`	An OTP connection object produced by `otp_connect`.
`location`	Numeric vector, Latitude/Longitude pair, e.g. 'c(53.48805, -2.24258)'
`fromLocation`	Logical. If TRUE (default) the isochrone will be generated from the `location`. If FALSE the isochrone will be generated to the `location`.
`format`	Character, required format of returned isochrone(s). Either JSON (returns GeoJSON) or SF (returns simple feature collection). Default is JSON.
`mode`	Character vector, mode(s) of travel. Valid values are: WALK, TRANSIT, BUS, RAIL, TRAM, SUBWAY. TRANSIT will use all available transit modes. Default is TRANSIT. WALK mode is automatically added to TRANSIT, BUS, RAIL, TRAM, and SUBWAY. Due to an OTP limitation this function is not suitable for CAR or BICYCLE modes.
`date`	Character, must be in the format mm-dd-yyyy. This is the desired date of travel. Only relevant for transit modes. Default is the current system date.
`time`	Character, must be in the format hh:mm:ss. If `arriveBy` is FALSE (the default) this is the desired departure time, otherwise the desired arrival time. Only relevant for transit modes. Default is the current system time.
`cutoffs`	Numeric vector, containing the cutoff times in seconds. for example: 'c(900, 1800, 2700)' would request 15, 30 and 60 minute isochrones. Can be a single value.
`batch`	Logical. If true, goal direction is turned off and a full path tree is built
`arriveBy`	Logical. Whether a trip should depart (FALSE) or arrive (TRUE) at the specified date and time. Default is FALSE.
`maxWalkDistance`	Numeric. The maximum distance (in meters) that the user is willing to walk. Default is NULL (the parameter is not passed to the API and the OTP default of unlimited takes effect). This is a soft limit in OTPv1 and is ignored if the mode is WALK only. In OTPv2 this parameter imposes a hard limit on WALK, CAR and BICYCLE modes (see: http://docs.opentripplanner.org/en/latest/OTP2-MigrationGuide/#router-config).
`walkReluctance`	A single numeric value. A multiplier for how bad walking is compared to being in transit for equal lengths of time. Default = 2.
`waitReluctance`	A single numeric value. A multiplier for how bad waiting for a transit vehicle is compared to being on a transit vehicle. This should be greater than 1 and less than `walkReluctance` (see API docs). Default = 1.
`transferPenalty`	Integer. An additional penalty added to boardings after the first. The value is in OTP's internal weight units, which are roughly equivalent to seconds. Set this to a high value to discourage transfers. Default is 0.
`minTransferTime`	Integer. The minimum time, in seconds, between successive trips on different vehicles. This is designed to allow for imperfect schedule adherence. This is a minimum; transfers over longer distances might use a longer time. Default is 0.
`extra.params`	A list of any other parameters accepted by the OTP API LIsochrone entry point. For advanced users. Be aware that otpr will carry out no validation of these additional parameters. They will be passed directly to the API. Do not pass 'fromPlace' or 'toPlace' to this function. These parameters are handled internally based on the values of `location` and `fromLocation`.

Returns a list. First element in the list is errorId. This is "OK" if OTP successfully returned the isochrone(s), otherwise it is "ERROR". The second element of list varies:

If errorId is "ERROR" then response contains the OTP error message.
If errorId is "OK" then response contains the the isochrone(s) in either GeoJSON format or as an sf object, depending on the value of the format argument.

The third element of the list is query which is a character string containing the URL that was submitted to the OTP API.

## Not run: 
otp_get_isochrone(otpcon, location = c(53.48805, -2.24258), cutoffs = c(900, 1800, 2700))

otp_get_isochrone(otpcon, location = c(53.48805, -2.24258), fromLocation = FALSE,
cutoffs = c(900, 1800, 2700), mode = "BUS")

## End(Not run)