def azimuth(other)
      rad2deg(@globe.inverse(phi, la, other.phi, other.la).last)
    end
def azimuth(other)
      rad2deg(@globe.inverse(phi, la, other.phi, other.la).last)
    end
Calculates azimuth (direction) to +other+ in degrees. Vincenty
 formula is used.

    kharkiv = Geo::Coord.new(50.004444, 36.231389)
    kyiv = Geo::Coord.new(50.45, 30.523333)

    kharkiv.azimuth(kyiv) # => 279.12614358262067