Hv plotting: external bugs an warnings

[lang-m]

xarray bug

In hv.vector we use xarray.arctan2 to compute the angle of the in-plane field. In there, we use the where argument. Due to a problem in xarray, this argument currently only works when passing a numpy.ndarray not with an xarray.DataArray. We can consider changing the arctan2 call in hv.py back to passing the xarray once this is fixed in xarray.

The problem is already known: pydata/xarray#7965

HoloViews warning

Holoviews currently shows a warning about a deprecated call to unique when creating a DynamicMap. I have added code to hide the warnings. This can be removed once fixed in the next HoloViews release. The relevant sections in hv.py have comments about this.

Question to and reply from the HoloViews team: https://discourse.holoviz.org/t/futurewarning-when-creating-a-dynamicmap/6108