Method: Geocoder::Calculations#random_point_near

Defined in:
lib/geocoder/calculations.rb

#random_point_near(center, radius, options = {}) ⇒ Object

Random point within a circle of provided radius centered around the provided point Takes one point, one radius, and an options hash. The points are given in the same way that points are given to all Geocoder methods that accept points as arguments. They 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

The options hash supports:

  • :units - :mi or :km Use Geocoder.configure(:units => …) to configure default units.

  • :seed - The seed for the random number generator



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# File 'lib/geocoder/calculations.rb', line 238

def random_point_near(center, radius, options = {})
  random = Random.new(options[:seed] || Random.new_seed)

  # convert to coordinate arrays
  center = extract_coordinates(center)

  earth_circumference = 2 * Math::PI * earth_radius(options[:units])
  max_degree_delta =  360.0 * (radius / earth_circumference)

  # random bearing in radians
  theta = 2 * Math::PI * random.rand

  # random radius, use the square root to ensure a uniform
  # distribution of points over the circle
  r = Math.sqrt(random.rand) * max_degree_delta

  delta_lat, delta_long = [r * Math.cos(theta), r * Math.sin(theta)]
  [center[0] + delta_lat, center[1] + delta_long]
end