html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,performed_via_github_app,issue
https://github.com/pydata/xarray/issues/6617#issuecomment-1133833687,https://api.github.com/repos/pydata/xarray/issues/6617,1133833687,IC_kwDOAMm_X85DlO3X,40182387,2022-05-22T07:09:33Z,2022-05-22T07:09:33Z,CONTRIBUTOR,"You're right, thanks for the help. It seems that orthogonal dimensions are now interpolated independently by calling SciPy's `interp1d` multiple times, which explains why passing `'extrapolate'` works.
This behaviour has been introduced in #4155,  in particular 7daad4fce3bf8ad9b9bc8e7baa104c476437e68d.

The documentation should be adapted to use @keewis's approach. I'd suggest including an example combining ""advanced interpolation"" and extrapolation, such as the one below:

```python
da = xr.DataArray(
    np.sin(0.3 * np.arange(20).reshape(5, 4)),
    [(""x"", np.arange(5)), (""y"", [0.1, 0.2, 0.3, 0.4])],
)
x = xr.DataArray([0.5, 1.5, 2.5, 3.5], dims=""z"")
y = xr.DataArray([0.15, 0.25, 0.35, 0.45], dims=""z"")
```

Without extrapolation:
```python
da.interp(x=x, y=y)
```
```
<xarray.DataArray (z: 4)>
array([ 0.55626357,  0.63496063, -0.46643289,         nan])
Coordinates:
    x        (z) float64 0.5 1.5 2.5 3.5
    y        (z) float64 0.15 0.25 0.35 0.45
Dimensions without coordinates: z
```

With extrapolation:
```python
da.interp(x=x, y=y, kwargs={'fill_value': None})
```
```
<xarray.DataArray (z: 4)>
array([ 0.55626357,  0.63496063, -0.46643289, -0.73507668])
Coordinates:
    x        (z) float64 0.5 1.5 2.5 3.5
    y        (z) float64 0.15 0.25 0.35 0.45
Dimensions without coordinates: z
```","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,1238838588