error in Landsat8-cog-ndvi-hvplot.iynb

[echoxiangzhou]

running the line in the Landsat8-cog-ndvi-hvplot.iynb

display(band1.hvplot(rasterize=True, width=600, height=400, cmap='viridis'))

results:

---------------------------------------------------------------------------
IndexError                                Traceback (most recent call last)
/srv/conda/envs/iocasdata/lib/python3.7/site-packages/xarray/core/utils.py in __len__(self)
    501         try:
--> 502             return self.shape[0]
    503         except IndexError:

IndexError: tuple index out of range

During handling of the above exception, another exception occurred:

TypeError                                 Traceback (most recent call last)
<timed eval> in <module>

/srv/conda/envs/iocasdata/lib/python3.7/site-packages/hvplot/plotting/core.py in __call__(self, x, y, kind, **kwds)
     70                 return pn.panel(plot, **panel_dict)
     71 
---> 72         return self._get_converter(x, y, kind, **kwds)(kind, x, y)
     73 
     74     def _get_converter(self, x=None, y=None, kind=None, **kwds):

/srv/conda/envs/iocasdata/lib/python3.7/site-packages/hvplot/converter.py in __call__(self, kind, x, y)
    942                 obj = DynamicMap(cbcallable, streams=[self.stream])
    943             else:
--> 944                 obj = method(x, y)
    945 
    946         if self.crs and self.project:

/srv/conda/envs/iocasdata/lib/python3.7/site-packages/hvplot/converter.py in rgb(self, x, y, z, data)
   1586             z = list(data.data_vars)[0]
   1587         data = data[z]
-> 1588         nbands = len(data.coords[bands])
   1589         if nbands < 3:
   1590             raise ValueError('Selected bands coordinate (%s) has only %d channels,'

/srv/conda/envs/iocasdata/lib/python3.7/site-packages/xarray/core/dataarray.py in __len__(self)
    541 
    542     def __len__(self) -> int:
--> 543         return len(self.variable)
    544 
    545     @property

/srv/conda/envs/iocasdata/lib/python3.7/site-packages/xarray/core/utils.py in __len__(self)
    502             return self.shape[0]
    503         except IndexError:
--> 504             raise TypeError("len() of unsized object")
    505 
    506 

TypeError: len() of unsized object

and package versions:

# Print package versions
print('xarray version: ', xr.__version__)
print('rasterio version: ', rasterio.__version__)
print('hvplot version: ', hvplot.__version__)

xarray version: 0.15.1
rasterio version: 1.1.3
hvplot version: 0.5.2