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Add the following checks for CF-1.4

5.6 Grid Mappings and Projects
Additional valid values of grid_mapping_name are:

lambert_cylindrical_equal_area
latitude_longitude
mercator
orthographic
vertical_perspective

7.3 Cell Methods
Requirements:

• The type of the cell_methods attribute is a string whose value is one or more blank separated word lists, each with the form

  dim1: [dim2: [dim3: ...]] method [where type1 [over type2]] [within|over days|years] [(comment)]
  

  where brackets indicate optional words. The valid values for dim1 [dim2 [dim3 ...] ] are the names of dimensions of the data variable, names of scalar coordinate variables of the data variable, valid standard names, or the word area. The valid values of method are contained in Appendix E. The valid values for type1 are the name of a string-valued auxiliary or scalar coordinate variable with a standard_name of area_type, or any string value allowed for a variable of standard_name of area_type. If type2 is a string-valued auxiliary coordinate variable, it is not allowed to have a leading dimension (the number of strings) of more than one. When the method refers to a climatological time axis, the suffixes for within and over may be appended.

Recommendations:

• If a data variable has any dimensions or scalar coordinate variables referring to horizontal, vertical or time dimensions, it should have a cell_methods attribute with an entry for each of these spatiotemporal dimensions or scalar coordinate variables. (The horizontal dimensions may be covered by an area entry.)

• Except for entries whose cell method is point, all numeric coordinate variables and scalar coordinate variables named by cell_methods should have bounds or climatology attributes.

In view of the problem raised by Thomas Lavergne on the email list in the thread "X and Y projection coordinate (center vs corner)", I propose that we insert the following clarification at the end of the introduction to section 4 of the CF standard:

The values of a coordinate variable or auxiliary coordinate variable indicate the locations of the gridpoints. The locations of the boundaries between cells are indicated by bounds variables (see section 7.1 on "Cell Boundaries"). If bounds are not provided, an application might reasonably assume the gridpoints to be at the centers of the cells, but we do not require that in this standard.

I don't believe that inserting this text would change the intention of the CF standard.

Second paragraph of 1.3 should read

We recommend that the NUG defined attribute Conventions be given the string value "CF-1.4" to identify datasets that conform to these conventions.

This mistake was spotted by Constantine Khroulev. We should remember to keep this sentence up-to-date in each version.

Jonathan