Improve CF Conformance: 5.8 Domain Variables

[jamesdoyle21]

5.8 Domain Variables
Requirements:

• Domain variables must have a dimensions attribute.

• The type of the dimensions attribute is a string whose value is a blank separated list of dimension names. All specified dimensions must exist in the file. The string may be empty.

• The dimensions of each variable named by the coordinates attribute must be a subset of zero or more of the dimensions named by the dimensions attribute, with two exceptions. First, a label variable which will have a trailing dimension for the maximum string length. Second a ragged array (Chapter 9, Discrete sampling geometries and Appendix H) uses special, more indirect, methods to connect the domain and coordinates.

• The dimensions of each variable named by the cell_measures attribute must be a subset of zero or more of the dimensions named by the dimensions attribute.

Recommendations:

• Domain variables should have a long_name attribute.

• Domain variables should not have any of the attributes marked in [attribute-appendix] as applicable to data variables except those which are also marked as applicable to domain variables.

[benjwadams]

Parts of these are in the develop_1_9 branch.

[benjwadams]

...which has now been merged in. I will review the changes and update this list.

[benjwadams]

#1089 implements point 4/4 in required section.