Hi All, Just a note to reassure everyone that I am receiving/following these recent comments questions and will compose a response next week after I unpack. In the meantime, please be aware that the ancestor search algorithm and the lateral search algorithm, as envisaged by the proposers, are not quite what Jonathan seems to think they are, so we need to do a better job of explaining them. Both searches should search no higher than the local apex group where the dimensions underlying the referring variable (and thus its coordinates) are defined. This is in general (and in practice) often lower down than the root group. In netCDF speak, the dimensions underlying the variable and the coordinate must be not only the same name, but the same ID (dimension IDs are unique in netCDF). Otherwise chaos ensues. The variable and the coordinate must both be in the scope (i.e., child groups) of the group where the dimension(s) are defined. That "feature" is due to the way that netCDF implements the Common Data Model (CDM). Hence ancestor search goes no higher than the group where the dimension(s) are defined, same as lateral search. This is the local apex group.
-- 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/144#issuecomment-429464117
