Class: Geodesics::Strategies::Lambert

Inherits:
Object
  • Object
show all
Defined in:
lib/geodesics/strategies/lambert.rb

Constant Summary collapse

INVERSE_FLATTENING =

WGS 84

298.257223563
FLATTENING = 
1.0 / INVERSE_FLATTENING
EQUATORIAL_RADIUS = 
6_378_137
CENTRAL_ANGLE = 
CentralAngles::Haversine.new

Instance Method Summary collapse

Constructor Details

#initialize(equatorial_radius: EQUATORIAL_RADIUS, flattening: FLATTENING, central_angle: CENTRAL_ANGLE) ⇒ Lambert

Returns a new instance of Lambert.



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# File 'lib/geodesics/strategies/lambert.rb', line 13

def initialize(
  equatorial_radius: EQUATORIAL_RADIUS,
  flattening: FLATTENING,
  central_angle: CENTRAL_ANGLE
)
  @equatorial_radius = equatorial_radius
  @flattening = flattening
  @central_angle = central_angle
end

Instance Method Details

#distance(point1, point2) ⇒ Object 



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# File 'lib/geodesics/strategies/lambert.rb', line 23

def distance(point1, point2)
  sigma = @central_angle.call(point1, point2)
  beta1 = parametric_latitude(point1.latitude)
  beta2 = parametric_latitude(point2.latitude)
  p = (beta1 + beta2) / 2
  q = (beta2 - beta1) / 2
  x = (sigma - sin(sigma)) * sin(p)**2 * cos(q)**2 / cos(sigma / 2)**2
  y = (sigma + sin(sigma)) * cos(p)**2 * sin(q)**2 / sin(sigma / 2)**2
  @equatorial_radius * (sigma - @flattening * (x + y) / 2)
end