def distance(other)
      @globe.inverse(phi, la, other.phi, other.la).first
    end
def distance(other)
      @globe.inverse(phi, la, other.phi, other.la).first
    end
Calculates distance to +other+ in SI units (meters). Vincenty
 formula is used.

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

    kharkiv.distance(kyiv) # => 410211.22377421556