Module: NciLocationCalc

Defined in:
lib/nci_location_calc.rb,
lib/nci_location_calc/version.rb

Constant Summary collapse

VERSION = 
"0.0.1"

Instance Method Summary collapse

Instance Method Details

#distance(loc1, loc2) ⇒ Object 



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# File 'lib/nci_location_calc.rb', line 5

def distance loc1, loc2

  #Reference: http://stackoverflow.com/questions/12966638/how-to-calculate-the-distance-between-two-gps-coordinates-without-using-google-m    
  rad_per_deg = Math::PI/180  # PI / 180
  rkm = 6371                  # Earth radius in kilometers
  rm = rkm * 1000             # Radius in meters

  dlat_rad = (loc2[0]-loc1[0]) * rad_per_deg  # Delta, converted to rad
  dlon_rad = (loc2[1]-loc1[1]) * rad_per_deg

  lat1_rad, lon1_rad = loc1.map {|i| i * rad_per_deg }
  lat2_rad, lon2_rad = loc2.map {|i| i * rad_per_deg }

  a = Math.sin(dlat_rad/2)**2 + Math.cos(lat1_rad) * Math.cos(lat2_rad) * Math.sin(dlon_rad/2)**2
  c = 2 * Math::atan2(Math::sqrt(a), Math::sqrt(1-a))

  rm * c # Delta in meters

end