issue_comments: 562652648

Hi, I was looking to some xarray padding function and get this issue. For the moment, I made a function of my own based on numpy.pad and xr.apply_ufunc When possible, it also pad associated coordinates. If it can be of any help here... Here it is: ``` def xpad(ds, dims={}): """ Padding of xarray. Coordinate are linearly padded if original coordinates are evenly spaced. Otherwise, no new coordinates are affected to padded axis. Padded dimension is named with prefix 'padded_'

Args:
    ds (xarray): xarray
    dims (dict): keys are dimensions along which to pad and values are padding tuple (see np.pad). (ex {'pulse:(10,0)})

Returns:
    (xarray) : same as input with padded axis. 
"""
mypad = [(0,0) for n in ds.dims if n not in dims.keys()]
mypad+=list(dims.values())
padded_ds = xr.apply_ufunc(np.pad, ds, mypad,input_core_dims=[list(dims.keys()),[]], output_core_dims=[['padded_'+d for d in dims.keys()]], keep_attrs=True)

for var, ext in dims.items():
    dvar = np.diff(ds[var])
    if np.allclose(dvar, dvar[0]):
        dvar = dvar[0]
        left_bound, right_bound  = (np.min(ds[var]).data, np.max(ds[var]).data) if dvar>0. else (np.max(ds[var]).data, np.min(ds[var]).data)
        extended_var = np.append(ds[var].data, np.max(ds[var]).data+np.arange(1,ext[1]+1)*dvar)
        extended_var = np.append(np.min(ds[var]).data+np.arange(-ext[0],0)*dvar, extended_var)
        padded_ds = padded_ds.assign_coords(**{'padded_'+var:extended_var})
    else:
        print('Coordinates {} are not evenly spaced, padding is impossible'.format(var))
return padded_ds

```