code: def great_circle_dist(lat1, lon1, lat2, lon2):
      
      radius = 6372795  # meters
  
      lat1 = math.radians(lat1)
      lon1 = math.radians(lon1)
      lat2 = math.radians(lat2)
      lon2 = math.radians(lon2)
  
      dlat = lat2 - lat1
      dlon = lon2 - lon1
  
      # formula from:
      # http://en.wikipedia.org/wiki/Haversine_formula#The_haversine_formula
      a = math.pow(math.sin(dlat / 2), 2)
      b = math.cos(lat1) * math.cos(lat2) * math.pow(math.sin(dlon / 2), 2)
      d = 2 * radius * math.asin(math.sqrt(a + b))
  
      return d
docs: Get the distance (in meters) between two lat/lon points
      via the Haversine formula.
  
      Parameters
      ----------
      lat1, lon1, lat2, lon2 : float
          Latitude and longitude in degrees.
  
      Returns
      -------
      dist : float
          Distance in meters.