The [original proposal](https://github.com/cf-convention/cf-conventions/issues/153#issue-390703403) suggests
> We recommend that netCDF files that follow these conventions indicate this by > setting the NUG defined global attribute Conventions to the string value > "CF-1.8" which also implies "UGRID-1.0". This says to me that the proposal is functionally equivalent to UGRID 1.0 being incorporated into CF in a new chapter that describes the UGRID that CF recognizes. It follows, I think, that CF checkers will be expected to check the UGRID conventions (unlike CRS-WKT, which does not need to be checked). Therefore there is a need for conformance rules and recommendations that cover UGRID _in relation to CF_. Does UGRID already have it's own conformance rules? For example, [when a data variable has mesh topology](http://ugrid-conventions.github.io/ugrid-conventions/#data-variables), it would need to be stated unambiguously whether or not the `coordinates` attribute is mandatory, and when it is present whether or not it should always contain the coordinate variables implied by the values of the `mesh`, `location`, and `location_index_set` data variable attributes. I do very much support UGRID being a part of CF, but think there are some important structural details that need to be worked out first. At the current time, having thought about all this again, I wonder if the best two options are: * Incorporate UGRID into CF into as a new chapter. * If that is not acceptable, simply drop this issue, and if people want to use UGRID they should say so in the `Convenions` attribute `"CF-1.9 UGRID-1.0"`. This would be the status quo approach, I think. In this case it would be up to the UGRID developers alone to ensure consistency with CF. Thanks, David -- 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/153#issuecomment-702679434 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].
