Coordinates get transformed to variables

[olgabot]

Code Sample, a copy-pastable example if possible

To get the data to reproduce the example: aws s3 sync s3://olgabot-maca/xarray-coordinates-to-variables/ . or download this .tar.gz file.

gist with code

Problem description

When I create a dataset, I set a bunch of metadata as coordinates, not variables:

But when I reload that exact same dataset with xr.open_dataset, the coordinates have be moved into variables!!

Interestingly, I think this is happening upon dataset creation because ds.variables already has the erroneous metadata:

Expected Output

I expected the coordinates and variables to be consistent between opening and closing the file

Output of xr.show_versions()

INSTALLED VERSIONS

commit: None
python: 3.6.3.final.0
python-bits: 64
OS: Linux
OS-release: 4.4.0-97-generic
machine: x86_64
processor: x86_64
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8
LOCALE: en_US.UTF-8

xarray: 0.10.0rc1-2-gf83361c
pandas: 0.20.3
numpy: 1.13.3
scipy: 0.19.1
netCDF4: None
h5netcdf: None
Nio: None
bottleneck: None
cyordereddict: None
dask: None
matplotlib: None
cartopy: None
seaborn: None
setuptools: 36.5.0.post20170921
pip: 9.0.1
conda: None
pytest: None
IPython: 6.1.0
sphinx: None

[shoyer]

@olgabot when I try to download your data file, I get the following error:

<Error>
<Code>AccessDenied</Code>
<Message>Access Denied</Message>
<RequestId>789A57CAD523F9C5</RequestId>
<HostId>
nC1x+xpJ3bqNZ2MwSYl4vnhMdIT9FHxmr5que9X6htROEla3mFvgIWYhxLK5DmfoPe282rNHzds=
</HostId>
</Error>

[olgabot]

Sorry about that, try again now. Damn permissions!

[shoyer]

@olgabot the CSV files in your tar file all seem to be aliases when I unzip them... maybe try uploading one of them directly?

[olgabot]

Ah sorry about that. Just re-tar'd and uploaded the dereferenced files. All of the files are in the bucket itself which can be viewed with aws s3 ls s3://olgabot-maca/xarray-coordinates-to-variables/

[shoyer]

@olgabot thanks for the report. The problem is spaces in your variable names -- if you replace them with underscores, everything works fine. See #1689 for a discussion of our options for fixing this in xarray.

[olgabot]

Thank you! Replacing with underscores works just fine, I'll do that for my data for now.

[shoyer]

Since we've figured this one out, I'm going to close it in favor of #1689.