Method: Geocoder::Calculations#endpoint

Defined in:
lib/geocoder/calculations.rb

#endpoint(start, heading, distance, options = {}) ⇒ Object

Given a start point, heading (in degrees), and distance, provides an endpoint. The starting point is given in the same way that points are given to all Geocoder methods that accept points as arguments. It can be:

  • an array of coordinates ([lat,lon])

  • a geocodable address (string)

  • a geocoded object (one which implements a to_coordinates method which returns a [lat,lon] array



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# File 'lib/geocoder/calculations.rb', line 269

def endpoint(start, heading, distance, options = {})
  radius = earth_radius(options[:units])

  start = extract_coordinates(start)

  # convert degrees to radians
  start = to_radians(start)

  lat = start[0]
  lon = start[1]
  heading = to_radians(heading)
  distance = distance.to_f

  end_lat = Math.asin(Math.sin(lat)*Math.cos(distance/radius) +
                Math.cos(lat)*Math.sin(distance/radius)*Math.cos(heading))

  end_lon = lon+Math.atan2(Math.sin(heading)*Math.sin(distance/radius)*Math.cos(lat),
                Math.cos(distance/radius)-Math.sin(lat)*Math.sin(end_lat))

  to_degrees [end_lat, end_lon]
end