# File lib/geo_ruby/simple_features/point.rb, line 44
      def spherical_distance(point,radius=6370997.0)
        deg_to_rad = 0.0174532925199433
        
        radlat_from = lat * deg_to_rad
        radlat_to = point.lat * deg_to_rad
        
        dlat = (point.lat - lat) * deg_to_rad
        dlon = (point.lon - lon) * deg_to_rad
 
        a = Math.sin(dlat/2)**2 + Math.cos(radlat_from) * Math.cos(radlat_to) * Math.sin(dlon/2)**2
        c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a))
        radius * c
      end