genutil.area_weights doesn't work with non-cartesian grids (most CMIP5 ocean grids)

[chaosphere2112]

This example outlines the issue:

import cdms2 as cdm
import genutil as gutil
infile = '/work/cmip5/historical/ocn/mo/thetao/cmip5.ACCESS1-0.historical.r1i1p1.mo.ocn.Omon.thetao.ver-1.latestX.xml'
f_h = cdm.open(infile)
mask = f_h('thetao',time=slice(0,1),lev=slice(0,1))(squeeze=1)
ocean_area_frac = gutil.area_weights(mask)

>>> ocean_area_frac = gutil.area_weights(mask)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/uvcdat/latest/lib/python2.7/site-packages/genutil/averager.py", line 188, in area_weights
    wt = __myGetAxisWeights(ds, 0, axisoptions)
  File "/usr/local/uvcdat/latest/lib/python2.7/site-packages/genutil/averager.py", line 54, in __myGetAxisWeights
    raise AveragerError, 'Bounds not available to compute weights for dimension: '+ax.id
genutil.averager.AveragerError: ('B', 'o', 'u', 'n', 'd', 's', ' ', 'n', 'o', 't', ' ', 'a', 'v', 'a', 'i', 'l', 'a', 'b', 'l', 'e', ' ', 't', 'o', ' ', 'c', 'o', 'm', 'p', 'u', 't', 'e', ' ', 'w', 'e', 'i', 'g', 'h', 't', 's', ' ', 'f', 'o', 'r', ' ', 'd', 'i', 'm', 'e', 'n', 's', 'i', 'o', 'n', ':', ' ', 'j')

Migrated from: CDAT/cdat#402

[durack1]

@chaosphere2112 @doutriaux1 same here

[doutriaux1]

@durack1 in the mean time you can try to use zonalmeans

[github-actions]

Marking issue as stale, since there has been no activity in 30 days.

Unless the issue is updated or the 'stale' tag is removed, this issue will be closed in 7 days.

[durack1]

@jasonb5 this is a pretty big standing issue, as many of the CMIP5 and now CMIP6 grids (both atmospheric and oceanic) are now non-cartesian, it would be great if these functions were updated to be grid aware and worked as you'd expect

[jypeter]

That would be nice. The least to do would be to print a warning telling the user to try to locate a CMIPn areacella or areacello variable matching his/her data

Some casual CMIPn data users don't know about areacellaandareacello. Telling people about these 2 variables in averager` and an averager tutorial could be useful as well

[durack1]

@jypeter not a bad suggestion, we might have to make this a little smarter, so only if a CMIPx file is being read, but I suppose a generic warning could also be useful