[CF-metadata] CF feature type trajectory (Ch. 9; May 10, 2011) and axis attribute

From: Jeffrey F. Painter <painter1>
Date: Thu, 07 Jul 2011 11:53:01 -0700

It looks as though you've been reviewing the public draft of the future
CF Conventions version 1.6. It's great that someone has been looking at it!

It seems to me that z in the examples of Appendix H (formerly designated
A9) plays the role of an auxiliary coordinate variable, although
technically it's not because there isn't (but should be) a 'coordinates'
attribute which lists auxiliary coordinate variables. I don't know why
axes are banned for auxiliary coordinate variables in the case of
trajectories. Something needs to be clarified here, or the examples
changed.

This was ticket 37. Are there any comments from Steve Hankin, the
moderator, or any of the other people who contributed to writing Chapter
9, or anyone else who knows more than me?

Thanks to all!
- Jeff Painter

On 7/7/11 5:13 AM, Chris Paver wrote:
> Dear List,
> I have been reviewing the use of the axis attribute as defined in Chapter 5, and
> comparing it to the trajectory example in the Chapter 9 document at A9.4. The
> Ch. 5 rules states that only a coordinate variable can have an axis attribute,
> whereas the auxiliary variables cannot. However, in Ch. 9, the single
> trajectory dimension is time, but the variable z contains the axis attribute. Is
> this a change to the rule as stated in Ch. 5, or a typo? I briefly looked over
> the other feature types in Ch. 9, and they all look to have the vertical
> variable listed with the axis attribute, so maybe it is a typo.
>
> Thanks,
> Chris
Received on Thu Jul 07 2011 - 12:53:01 BST