make_isodistance: Make Isodistance

In Chrisjb/RDistanceMatrix: Useful Functions For Building Isochrones And Related Analysis

Description

Generates an isodistance polygon for network distances to/from a specified location.

Usage

make_isodistance(
  site,
  distance,
  direction = c("out", "in"),
  detail = "medium",
  mode = c("driving", "walking", "cycling", "transit"),
  departing = FALSE,
  tz = Sys.timezone(),
  init_grid_size = 5,
  google_api_key = Sys.getenv("google_api_key")
)

Arguments

site	either a data.frame with the columns 'lat' and 'lng' or a character string to be geocoded.
distance	a numeric value in meters. This is the network distance from the site to the isodistance extents.
direction	either 'in' or 'out'. In generates an isodistance from multiple origins to the site. Out goes from the site to multiple destinations.
detail	'low', 'medium' or 'high' level of detail in the isodistance. High will produce the most granular detail but will use more API credits.
mode	a character string for the mode of travel. Possible values are 'driving', 'cycling', 'transit', or 'walking'
departing	optional parameter for getting distance in traffic. Google maps may route differently to avoid heavy traffic, changing the distance at peak times. If set, takes the format "YYYY-MM-DD HH:MM:SS" in the local time of the origin country.
tz	if departure time is set, timezone defaults to the user's timezone as per 'Sys.timezone'. Where the timezone of the 'site' differs from the user timezone, specify the 'site' timezone here. tz is a character string that must be a time zone that is recognized by the user's OS.
init_grid_size	an integer from 2 to 5. Adjust if want to change number of points to pick up in the initial guess stage before adding detail.
google_api_key	the google maps API key. This can be generated from the google cloud console and set with set_google_api

Value

an sf polygon

Examples

walk_radius <- make_isodistance('EC2R 8AH', distance = 2000, direction = 'out', mode = 'walking')

Chrisjb/RDistanceMatrix documentation built on Jan. 27, 2021, 9:12 p.m.