Class: Iata::Coordinates

Inherits:
Object
  • Object
show all
Defined in:
lib/iata/coordinates.rb

Overview

Geographic coordinates (WGS-84) for an IATA airport entry.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(latitude: nil, longitude: nil) ⇒ Coordinates

Returns a new instance of Coordinates.



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# File 'lib/iata/coordinates.rb', line 8

def initialize(latitude: nil, longitude: nil)
  @latitude = latitude&.to_f
  @longitude = longitude&.to_f
end

Instance Attribute Details

#latitude ⇒ Object (readonly)

Returns the value of attribute latitude.



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# File 'lib/iata/coordinates.rb', line 6

def latitude
  @latitude
end

#longitude ⇒ Object (readonly)

Returns the value of attribute longitude.



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# File 'lib/iata/coordinates.rb', line 6

def longitude
  @longitude
end

Instance Method Details

#==(other) ⇒ Object 



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# File 'lib/iata/coordinates.rb', line 17

def ==(other)
  other.is_a?(Coordinates) &&
    latitude == other.latitude &&
    longitude == other.longitude
end

#distance_to(other) ⇒ Object

Great-circle distance in kilometres to another Coordinates, using the haversine formula. Returns nil if either side lacks coordinates.



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# File 'lib/iata/coordinates.rb', line 31

def distance_to(other)
  return nil if latitude.nil? || longitude.nil? ||
                other.latitude.nil? || other.longitude.nil?

  earth_radius_km = 6371.0
  d_lat = (other.latitude - latitude) * (Math::PI / 180)
  d_lon = (other.longitude - longitude) * (Math::PI / 180)
  a = (Math.sin(d_lat / 2)**2) +
      (Math.cos(latitude * (Math::PI / 180)) *
       Math.cos(other.latitude * (Math::PI / 180)) *
       (Math.sin(d_lon / 2)**2))
  2 * earth_radius_km * Math.asin(Math.sqrt(a))
end

#to_a ⇒ Object 



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# File 'lib/iata/coordinates.rb', line 13

def to_a
  [latitude, longitude].compact
end

#to_s ⇒ Object 



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# File 'lib/iata/coordinates.rb', line 23

def to_s
  return '' if latitude.nil? || longitude.nil?

  format('%<lat>.4f %<lon>.4f', lat: latitude, lon: longitude)
end