#173: clarify the dimensions of ancillary variables
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Reporter: jonathan | Owner: cf-conventions@…
Type: defect | Status: new
Priority: medium | Milestone:
Component: cf-conventions | Version:
Keywords: |
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The purpose of ancillary variables (Section 3.4 of the convention) is to
provide metadata about individual values in data variables. Given this
purpose, I believe that an ancillary data variable should not have any
dimensions which its data variable does not have. To clarify this, I
propose that the following should be appended to the first paragraph of
Section 3.4: "The dimensions of an ancillary variable should be the same
as or a subset of the dimensions of the data variable with which it is
associated by the `ancillary_variables` attribute, but the order of the
dimensions is not restricted." This text corresponds to a similar sentence
in Section 7.2 about cell measures variables.
I'm proposing this as a defect ticket because this is my understanding of
what the convention intends. Please comment if you don't think so. Thanks.
Jonathan
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Ticket URL: <https://cf-trac.llnl.gov/trac/ticket/173>
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