pyart.core.Grid.to_xarray returns 1-dimensional lon-lat instead of 2-dimensional

[Vforcell]

@mgrover1
## Context

In pyart.core.Grid.to_xarray, only one dimension of the longitude (resp. latitude) 2-dimensional array is used to create the xarray object.

By doing so, we make the assumption that the Grid is regular in longitude and latitude, which is not.

This involves displacements in the Grid object when plotting using longitude and latitude. This displacement increases with the distance to the origin of the Grid. At 100km range, there is a displacement of ~7km when using 1-dimensional lon / lat compared to the 2-dimensional lon / lat coming from Grid.get_point_longitude_latitude function.

Solution

lon / lat coordinates in the xarray.Dataset object should be defined as 2-dimensional along (y, x).

"lat": (["y"], lat[:, 0]), ---> "lat": (["y", "x"], lat)
"lon": (["x"], lon[0, :]), ---> "lon": (["y", "x"], lon)