Error when overlaying hv.Tiles with a gv.Points element that has wrong xlim/ylim defined, with Matplotlib

[maximlt]

This snippet sets the xlim and ylim opts of a gv.Points element to values that make no sense, and tries to overlay this element to an hv.Tiles element. Even if it's expected that there's some kind of error, the one I got with the Matplotlib backend felt way too cryptic, so I'm opening an issue to see if there would be a way to catch the error and improve the error message.

import geoviews as gv
import holoviews as hv
import cartopy

import pandas as pd
import numpy as np

gv.extension('matplotlib')

df_pts = pd.DataFrame(np.random.randn(100, 2), columns=['x', 'y'])
points = gv.Points(df_pts, crs=cartopy.crs.PlateCarree()).opts(xlim=(20000000, 40000000), ylim=(20000000, 400000000))
tiles = hv.element.tile_sources['EsriImagery']()
tiles * points

WARNING:param.GeoOverlayPlot07187: No plotting class for Tiles type and matplotlib backend found. 

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
~/miniconda3/envs/hvplot-dev37/lib/python3.7/site-packages/PIL/ImageFile.py in _save(im, fp, tile, bufsize)
    503     try:
--> 504         fh = fp.fileno()
    505         fp.flush()

AttributeError: '_idat' object has no attribute 'fileno'

During handling of the above exception, another exception occurred:

SystemError                               Traceback (most recent call last)
~/miniconda3/envs/hvplot-dev37/lib/python3.7/site-packages/IPython/core/formatters.py in __call__(self, obj, include, exclude)
    968 
    969             if method is not None:
--> 970                 return method(include=include, exclude=exclude)
    971             return None
    972         else:

~/miniconda3/envs/hvplot-dev37/lib/python3.7/site-packages/holoviews/core/dimension.py in _repr_mimebundle_(self, include, exclude)
   1314         combined and returned.
   1315         """
-> 1316         return Store.render(self)
   1317 
   1318 

~/miniconda3/envs/hvplot-dev37/lib/python3.7/site-packages/holoviews/core/options.py in render(cls, obj)
   1403         data, metadata = {}, {}
   1404         for hook in hooks:
-> 1405             ret = hook(obj)
   1406             if ret is None:
   1407                 continue

~/miniconda3/envs/hvplot-dev37/lib/python3.7/site-packages/holoviews/ipython/display_hooks.py in pprint_display(obj)
    280     if not ip.display_formatter.formatters['text/plain'].pprint:
    281         return None
--> 282     return display(obj, raw_output=True)
    283 
    284 

~/miniconda3/envs/hvplot-dev37/lib/python3.7/site-packages/holoviews/ipython/display_hooks.py in display(obj, raw_output, **kwargs)
    250     elif isinstance(obj, (CompositeOverlay, ViewableElement)):
    251         with option_state(obj):
--> 252             output = element_display(obj)
    253     elif isinstance(obj, (Layout, NdLayout, AdjointLayout)):
    254         with option_state(obj):

~/miniconda3/envs/hvplot-dev37/lib/python3.7/site-packages/holoviews/ipython/display_hooks.py in wrapped(element)
    144         try:
    145             max_frames = OutputSettings.options['max_frames']
--> 146             mimebundle = fn(element, max_frames=max_frames)
    147             if mimebundle is None:
    148                 return {}, {}

~/miniconda3/envs/hvplot-dev37/lib/python3.7/site-packages/holoviews/ipython/display_hooks.py in element_display(element, max_frames)
    190         return None
    191 
--> 192     return render(element)
    193 
    194 

~/miniconda3/envs/hvplot-dev37/lib/python3.7/site-packages/holoviews/ipython/display_hooks.py in render(obj, **kwargs)
     66         renderer = renderer.instance(fig='png')
     67 
---> 68     return renderer.components(obj, **kwargs)
     69 
     70 

~/miniconda3/envs/hvplot-dev37/lib/python3.7/site-packages/holoviews/plotting/renderer.py in components(self, obj, fmt, comm, **kwargs)
    448             return data, {}
    449         else:
--> 450             html = self._figure_data(plot, fmt, as_script=True, **kwargs)
    451         data['text/html'] = html
    452 

~/miniconda3/envs/hvplot-dev37/lib/python3.7/site-packages/holoviews/plotting/mpl/renderer.py in _figure_data(self, plot, fmt, bbox_inches, as_script, **kwargs)
    173                 pass
    174             bytes_io = BytesIO()
--> 175             fig.canvas.print_figure(bytes_io, **kw)
    176             data = bytes_io.getvalue()
    177 

~/miniconda3/envs/hvplot-dev37/lib/python3.7/site-packages/matplotlib/backend_bases.py in print_figure(self, filename, dpi, facecolor, edgecolor, orientation, format, bbox_inches, pad_inches, bbox_extra_artists, backend, **kwargs)
   2259                         orientation=orientation,
   2260                         bbox_inches_restore=_bbox_inches_restore,
-> 2261                         **kwargs)
   2262             finally:
   2263                 if bbox_inches and restore_bbox:

~/miniconda3/envs/hvplot-dev37/lib/python3.7/site-packages/matplotlib/backend_bases.py in wrapper(*args, **kwargs)
   1667             kwargs.pop(arg)
   1668 
-> 1669         return func(*args, **kwargs)
   1670 
   1671     return wrapper

~/miniconda3/envs/hvplot-dev37/lib/python3.7/site-packages/matplotlib/backends/backend_agg.py in print_png(self, filename_or_obj, metadata, pil_kwargs, *args)
    509         mpl.image.imsave(
    510             filename_or_obj, self.buffer_rgba(), format="png", origin="upper",
--> 511             dpi=self.figure.dpi, metadata=metadata, pil_kwargs=pil_kwargs)
    512 
    513     def print_to_buffer(self):

~/miniconda3/envs/hvplot-dev37/lib/python3.7/site-packages/matplotlib/image.py in imsave(fname, arr, vmin, vmax, cmap, format, origin, dpi, metadata, pil_kwargs)
   1614         pil_kwargs.setdefault("format", format)
   1615         pil_kwargs.setdefault("dpi", (dpi, dpi))
-> 1616         image.save(fname, **pil_kwargs)
   1617 
   1618 

~/miniconda3/envs/hvplot-dev37/lib/python3.7/site-packages/PIL/Image.py in save(self, fp, format, **params)
   2233 
   2234         try:
-> 2235             save_handler(self, fp, filename)
   2236         finally:
   2237             # do what we can to clean up

~/miniconda3/envs/hvplot-dev37/lib/python3.7/site-packages/PIL/PngImagePlugin.py in _save(im, fp, filename, chunk, save_all)
   1347         _write_multiple_frames(im, fp, chunk, rawmode)
   1348     else:
-> 1349         ImageFile._save(im, _idat(fp, chunk), [("zip", (0, 0) + im.size, 0, rawmode)])
   1350 
   1351     if info:

~/miniconda3/envs/hvplot-dev37/lib/python3.7/site-packages/PIL/ImageFile.py in _save(im, fp, tile, bufsize)
    510             if o > 0:
    511                 fp.seek(o)
--> 512             e.setimage(im.im, b)
    513             if e.pushes_fd:
    514                 e.setfd(fp)

SystemError: tile cannot extend outside image

Note that here tile doesn't refer to a geo-tile, it's related to PIL.

Removing .opts(xlim=(20000000, 40000000), ylim=(20000000, 400000000)) fixes the code, i.e. there's no more error (but of course the tiles are not plotted, since there's no matplotlib implementation for holoviews Tiles elements).

[jbednar]

Is there a good reason not to have Tiles plotting for mpl in HoloViews, given that we have it for GeoViews?