I could not find any discussion in the specs about how to indicate that two variables are part of a vector pair such as (u,v). In theory one can infer the relationship from the long-name, but it would seem to be useful to have a more direct means to indicate this relationship.
I see at least 4 different approaches to this:
1. Each variable that is part of a vector has an attribute that names the partner component. u:vector_partner = ?v" There is also an attribute that specifies the component index: u:vector_index=1 Others may want vectors with more components, in which case naming the partners becomes more problematic. And then one would also want an attribute that specifies the total number of components u:vector_length=2
2. Each vector component has an attribute that names the entire vector rather than the partner. u:vector_name=?u-v?. There would also be an attribute for specifying the vector component index as in (1) above. This approach is more scalable for longer vectors, but tools would need to search through all variables to find the partner components.
3. Have a separate variable which is a vector of strings. Each string names the list of component variables with some standard separator. E.g., ?u,v?, ?mx, my?, ?
4. Combine components into one variable with an extra vector index dimension. But this seems to be contrary to CF conventions for naming variables. It is also not very friendly to the tools that we are currently using.
Thanks in advance,
- Tom
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Received on Thu Oct 27 2016 - 13:23:43 BST
