ValueError: Invalid units: sigma must be dimensionless.

[Jack Yu]

Hi, 

I got an error when trying to load an netCDF file using iris.load().  It looks like this:

http://nbviewer.ipython.org/gist/qAp/212122b92a881ef30216/iris_test.ipynb

I am not very familiar with the CF conventions and suspected that it was because different variables have different dimensions, or because some created dimensions do not have a corresponding variable.  However, this does not seem to be the case.

Has anyone seen this before or know what might be the cause?

Thanks

[Filipe Pires Alvarenga Fernandes]

Hi Jack,

What version of iris are you using?  There were a few changes on how iris deals with dimensionless units that might help your case.

1) Units "no units" now are treated are dimensionless:

https://github.com/SciTools/iris/pull/1106

https://github.com/SciTools/iris/pull/1483

2) The `aux_factory` now it issues a warning instead of raising a ValueError:

https://github.com/SciTools/iris/pull/1485

The second will not guarantee that the Auxiliary Coordinate will be automatically built!  But you will be able to get the data cube, slice it be "sigma" or even build the z-coord yourself.

-Filipe

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[Jack Yu]

Hi Felipe,

The version is 1.7.4-DEV

In [1]: import iris

In [2]: iris.__version__

Out[2]: '1.7.4-DEV'

In [3]:

Is this the version you referred to?

[Filipe Pires Alvarenga Fernandes]

Hi Jack,

I was the changes I mentioned went towards iris 1.8.0-DEV and your 1.7.4-DEV will not work.  See the notebook below:

http://nbviewer.ipython.org/gist/ocefpaf/0a2fcbfca39ff783859a

Hope that helps,

-Filipe

On Sun, Mar 1, 2015 at 10:36 PM, Jack Yu <lla...@gmail.com> wrote:

Hi Felipe,

The .nc file can be found at

https://drive.google.com/file/d/0B68-5koyGA7IOG9ydVhkbVh1SUU/view?usp=sharing

Let me know if you want the data to be shared some other way.

Thanks

On Mon, Feb 16, 2015 at 7:25 PM, Filipe Pires Alvarenga Fernandes <oce...@gmail.com> wrote:

On Thu, Feb 12, 2015 at 10:36 PM, Jack Yu <lla...@gmail.com> wrote:

Hi Felipe,

The version is 1.7.4-DEV

In [1]: import iris

In [2]: iris.__version__

Out[2]: '1.7.4-DEV'

In [3]:

Is this the version you referred to?

 

Yes, you should have everything I mentioned in that release.  Not sure about what might be happening there.

Can you make a small sample of that data available online so we can test it?

-Filipe