Hello @JimBiardCics , I agree that you can parse the cited NUG sentence into either of the logical constructs you mention [above](https://github.com/cf-convention/cf-conventions/issues/174#issuecomment-596816563), but I don't believe it makes sense to parse the sentence in isolation. I believe that the context in which the sentence occurs in makes it clear that it is defining a coordinate variable. It is the first reference to "coordinate variable" within the "Coordinate Variable" section, and there is no other phrase in the document which can plausibly be considered as defining a coordinate variable. The construct `IF coordinate variable THEN ...` is meaningless without a definition which allows `IF coordinate variable` to be evaluated.
I agree with your suggestion in your [latest post](https://github.com/cf-convention/cf-conventions/issues/174#issuecomment-596816962). There has been frequent reference in this discussion to the concept of a **data variable**, and this phrase is also used 81 times in the version 1.9 draft of the CF Convention, but it is not currently defined in the terminology section. It might help to add a definition for this important term, and include you phrase. For example: **data variable** NetCDF variables which are neither **dimension coordinate variables** nor **grid mapping variables** are **data variables**. If a one-dimensional data variable is not a dimension coordinate variable, it must not have the same name as its dimension. I'd welcome any suggestions which can improve on the first line of this definition: I don't particularly like the fact that a **data variable** is defined in terms of what it isn't, but that looks to me to be an accurate reflection of the status quo. I've stated that a **data variable** is not a **grid mapping variable** because Appendix A treats them as distinct concepts. I've modified your phrase, replacing **coordinate variable** with **dimension coordinate variable**: a modification in terminology which had some support earlier in this discussion. -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://github.com/cf-convention/cf-conventions/issues/174#issuecomment-597043122 This list forwards relevant notifications from Github. It is distinct from [email protected], although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to [email protected].
