def METHOD_NAME(lat1, lon1, lat2, lon2):
     if np.isnan(lat1) or np.isnan(lat1) or np.isnan(lon1) or np.isnan(lon2):
         return -1
     if lat1 < 36 or lon1 < 127 or lat2 < 36 or lon2 < 127:
         return -1
     if lat1 > 38 or lon1 > 128 or lat2 > 38 or lon2 > 128:
         return -1
     p1 = np.array(utm.from_latlon(lat1, lon1)[0:2])
     p2 = np.array(utm.from_latlon(lat2, lon2)[0:2])
     err_l2norm = np.linalg.norm(p1-p2) # l2norm = np.sqrt(np.sum((p1-p2)**2))
     return err_l2norm