Module: MkCoord::Trigonometric

Defined in:
lib/mk_coord/trigonometric.rb

Class Method Summary collapse

Class Method Details

.compute_alpha(lambda, beta, eps) ⇒ Object

α の計算

  • α = arctan((-sinβ sinε + cosβ sinλ cosε ) / cosβ cosλ)

@param: lambda (unit: rad) @param: beta (unit: rad) @param: eps (unit: rad) @return: alpha (unit: rad)



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# File 'lib/mk_coord/trigonometric.rb', line 54

def compute_alpha(lambda, beta, eps)
  a = -Math.sin(beta) * Math.sin(eps) \
    +  Math.cos(beta) * Math.sin(lambda) * Math.cos(eps)
  b =  Math.cos(beta) * Math.cos(lambda)
  alpha = Math.atan2(a, b)
  alpha %= PI2 if a < 0
  return alpha
rescue => e
  raise
end

.compute_beta(alpha, delta, eps) ⇒ Object

β の計算

  • β = arcsisn((sinδ cosε - cosδ sinα sinε )

@param: alpha (unit: rad) @param: delta (unit: rad) @param: eps (unit: rad) @return: lambda (unit: rad)



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# File 'lib/mk_coord/trigonometric.rb', line 36

def compute_beta(alpha, delta, eps)
  a = Math.sin(delta) * Math.cos(eps) \
    - Math.cos(delta) * Math.sin(alpha) * Math.sin(eps)
  return Math.asin(a)
rescue => e
  raise
end

.compute_delta(lambda, beta, eps) ⇒ Object

δ の計算

  • δ = arcsisn((sinβ cosε + cosβ sinλ sinε )

@param: lambda (unit: rad) @param: beta (unit: rad) @param: eps (unit: rad) @return: delta (unit: rad)



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# File 'lib/mk_coord/trigonometric.rb', line 75

def compute_delta(lambda, beta, eps)
  a = Math.sin(beta) * Math.cos(eps) \
    + Math.cos(beta) * Math.sin(lambda) * Math.sin(eps)
  return Math.asin(a)
rescue => e
  raise
end

.compute_lambda(alpha, delta, eps) ⇒ Object

λ の計算

  • λ = arctan((sinδ sinε + cosδ sinα cosε ) / cosδ cosα)

@param: alpha (unit: rad) @param: delta (unit: rad) @param: eps (unit: rad) @return: lambda (unit: rad)



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# File 'lib/mk_coord/trigonometric.rb', line 15

def compute_lambda(alpha, delta, eps)
  a = Math.sin(delta) * Math.sin(eps) \
    + Math.cos(delta) * Math.sin(alpha) * Math.cos(eps)
  b = Math.cos(delta) * Math.cos(alpha)
  lambda = Math.atan2(a, b)
  lambda %= PI2 if lambda < 0
  return lambda
rescue => e
  raise
end