|  General case | 
                        
                        
                          
                            - Feature values need to be positive
 
                            | 
                        
                        
                          |   | 
                          
                            - Done by translating the entire feature range
 
                            | 
                        
                        
                          
                            - Feature values in 
  and   need to add up to the same mass 
                            | 
                          
                        
                          |   | 
                          
                            - Normalization may not always be suitable
 
                            | 
                        
                        
                           | 
                          
                        
                          
                            - Bank of 
  is sum of feature values of   and vice versa 
                            | 
                          
                        
                          
                            - Parameter 
 : ground distance from ordinary regions to bank 
                            | 
                          
                        
                          
                            - Bank to bank distance is 0
 
                            | 
                          
                        
                          
                              and   become matrices of size   
                            | 
                          
                        
                          
                            - Metric? Yes, if ground distance is a metric
 
                            | 
                          
                        
                           |