| 3 | |

| 4 | This proposal introduces a coordinate system variable which is |

| 5 | separate from the data variable. The coordinate system variable points to the |

| 6 | grid mapping and the projection coordinates. The data variable points to one or |

| 7 | more coordinate system variables. The advantage of this is that it directly |

| 8 | associates the grid mapping and the projection coordinates, and it saves having |

| 9 | to make the same association on every data variable. I would say that this is |

| 10 | an attractive idea, and it is quite natural to introduce this abstraction as a |

| 11 | way of interpreting the file. However, I think it would be inconsistent to |

| 12 | separate the coordinate system from the data variable *only* in this rather |

| 13 | specialised case, while we do not do it in the commoner situations where the |

| 14 | coordinate system is defined by the 1D coordinate variables, or by 2D lat-lon |

| 15 | auxiliary coordinate variables. Also, this abstraction may make the file harder |

| 16 | to understand and to use by simple programs or inexpert users. Users are |

| 17 | accustomed to seeing the coordinates attached to the data variable, which seems |

| 18 | an obvious approach. ''Jonathan'' |