Dear Randy

I think the answer is Yes and No! Only a data variable can have cell_methods,
but there is no prohibition on referring to a data variable as an aux coord var
by pointing to it from the coordinates attribute of another data variable.
So the air_pressure variable could be a data variable with an appropriate
cell_methods attribute, which would take the form "PIXEL: median" where PIXEL
is the name of some dimension which was collapsed to calculate the median.
Maybe this dimension does not exist, though? In that case I think it might
make sense to put "area: median". This would mean the median of all the values
within the area of that cell.

Cheers

Jonathan

----- Forwarded message from "[email protected]" 
<[email protected]> -----

> From: "[email protected]" <[email protected]>
> To: [email protected]
> Date: Thu, 27 Feb 2014 11:30:02 -0500
> Subject: [CF-metadata] can a cell method be an attribute of an auxiliary
>       coordinate variable ?
> 
>  
>  Dear All:
>   
>  i have a question ....
>   
>  We have a product containing an array of wind vectors (discrete sampling 
> geometry of type point) all derived from consecutive scenes of hyper 
> spectral imagery.
>   
>  One of the auxiliary coordinate variables is the air pressure.  This air 
> pressure is the median value of the imagery pixels used to derive the wind 
> vector using a pattern recognition algorithm.
>   
>  There are no specific coordinates for the pixels that were used to derive 
> the wind vector, but it would be useful to identify that the air pressure 
> associated with the wind vector is a median value.
>   
>  Does it make sense to do the following in the specification of the air 
> pressure auxiliary coordinate variable ?
>   
>  float pressure (number_of_wind_vectors);
>   
>     standard_name = "air_pressure"
>   
>     cell_methods = "air_pressure: median"
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