id,node_id,number,title,user,state,locked,assignee,milestone,comments,created_at,updated_at,closed_at,author_association,active_lock_reason,draft,pull_request,body,reactions,performed_via_github_app,state_reason,repo,type
686461572,MDU6SXNzdWU2ODY0NjE1NzI=,4378,Plotting when Interval coordinate is timedelta-based,500246,open,0,,,2,2020-08-26T16:36:27Z,2022-04-18T21:55:15Z,,CONTRIBUTOR,,,,"<!-- Please do a quick search of existing issues to make sure that this has not been asked before. -->

**Is your feature request related to a problem? Please describe.**

The xarray plotting interface supports coordinates containing `pandas.Interval` iff those intervals contain numbers.  It fails when those intervals contain `pandas.Timedelta`:

```python
import numpy as np
import pandas as pd
import xarray as xr

da = xr.DataArray(
        np.arange(10),
        dims=(""x"",),
        coords={""x"": [pd.Interval(i, i+1) for i in range(10)]})
da.plot()  # works

da = xr.DataArray(
        np.arange(10),
        dims=(""x"",),
        coords={""x"": [pd.Interval(
            d-pd.Timestamp(""2000-01-01""),
            d-pd.Timestamp(""2000-01-01"")+pd.Timedelta(""1H""))
            for d in pd.date_range(""2000-01-01"", ""2000-01-02"", 10)]})
da.plot()  # fails
```

The latter fails with:

```
Traceback (most recent call last):
  File ""mwe82.py"", line 18, in <module>
    da.plot()  # fails
  File ""/data/gholl/miniconda3/envs/py38/lib/python3.8/site-packages/xarray/plot/plot.py"", line 446, in __call__
    return plot(self._da, **kwargs)
  File ""/data/gholl/miniconda3/envs/py38/lib/python3.8/site-packages/xarray/plot/plot.py"", line 200, in plot
    return plotfunc(darray, **kwargs)
  File ""/data/gholl/miniconda3/envs/py38/lib/python3.8/site-packages/xarray/plot/plot.py"", line 302, in line
    _ensure_plottable(xplt_val, yplt_val)
  File ""/data/gholl/miniconda3/envs/py38/lib/python3.8/site-packages/xarray/plot/utils.py"", line 551, in _ensure_plottable
    raise TypeError(
TypeError: Plotting requires coordinates to be numeric or dates of type np.datetime64, datetime.datetime, cftime.datetime or pd.Interval.
```

This error message is somewhat confusing, because the coordinates _are_ ""dates of type (...) pd.Interval"", but perhaps a timedelta is not considered a date.

**Describe the solution you'd like**

I would like that I can use the xarray plotting interface for any pandas.Interval coordinate, including `pandas.Timestamp` and `pandas.Timedelta`.  

**Describe alternatives you've considered**

I'll ""manually"" calculate the midpoints and use those as a timedelta coordinate instead.

**Additional context**

It seems that regular timedeltas aren't really supported either, although they don't cause an error message, they rather produce [incorrect results](https://stackoverflow.com/q/50717534).  There's probably a related issue somewhere, but I can't find it now.","{""url"": ""https://api.github.com/repos/pydata/xarray/issues/4378/reactions"", ""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,,13221727,issue
203630267,MDU6SXNzdWUyMDM2MzAyNjc=,1234,`where` grows new dimensions for unrelated variables,500246,open,0,,,5,2017-01-27T13:02:34Z,2022-04-18T16:04:16Z,,CONTRIBUTOR,,,,"In the example below, the dimensionality for data variable `y` grows from `(b)` to `(b, a)` after calling the dataset `where` method.  This behaviour does not appear to be documented.  Is it a bug?

```
    In [46]: ds = xarray.Dataset({""x"": ((""a"", ""b""), arange(25).reshape(5,5)+100), ""y"": (""b"", arange(5)-100)}, {""a"": arange(5), ""b"": arange(5)*2, ""c"": ((""a"",), list(""ABCDE""))})
    
    In [47]: print(ds)
    <xarray.Dataset>
    Dimensions:  (a: 5, b: 5)
    Coordinates:
      * b        (b) int64 0 2 4 6 8
        c        (a) <U1 'A' 'B' 'C' 'D' 'E'
      * a        (a) int64 0 1 2 3 4
    Data variables:
        x        (a, b) int64 100 101 102 103 104 105 106 107 108 109 110 111 ...
        y        (b) int64 -100 -99 -98 -97 -96
    
    In [69]: ds.where((ds.c>='A') & (ds.c<='C'))
    Out[69]: 
    <xarray.Dataset>
    Dimensions:  (a: 5, b: 5)
    Coordinates:
      * b        (b) int64 0 2 4 6 8
        c        (a) <U1 'A' 'B' 'C' 'D' 'E'
      * a        (a) int64 0 1 2 3 4
    Data variables:
        x        (a, b) float64 100.0 101.0 102.0 103.0 104.0 105.0 106.0 107.0 ...
        y        (b, a) float64 -100.0 -100.0 -100.0 nan nan -99.0 -99.0 -99.0 ...
```
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