What happened?

When trying to plot a 2d DataArray that has one of the 2 coordinates as datetime with da.plot.imshow, the following error is returned:

TypeError: ufunc 'isfinite' not supported for the input types, and the inputs could not be safely coerced to any supported types according to the casting rule ''safe''

I know that I can use pcolormesh instead but on large arrays, imshow is much faster. It also behaves nicer with transparency and interpolation so or regularly sampled data, I find imshow a better choice.

Here is a minimal working example:

```python import numpy as np from xarray import DataArray from pandas import date_range

time = date_range('2020-01-01', periods=7, freq='D') y = np.linspace(0, 10, 11) da = DataArray( np.random.rand(time.size, y.size), coords=dict(time=time, y=y), dims=('time', 'y') )

da.plot.imshow(x='time', y='y') ```

What did you expect to happen?

I suggest the following solution which can be added after https://github.com/pydata/xarray/blob/4da7fdbd85bb82e338ad65a532dd7a9707e18ce0/xarray/plot/plot.py#L1366

python left, right = map(date2num, (left, right))

and then adding: python ax.xaxis_date() plt.setp(ax.get_xticklabels(), rotation=30, ha='right')

Minimal Complete Verifiable Example

```Python import numpy as np from xarray import DataArray from pandas import date_range

creating the data

time = date_range('2020-01-01', periods=7, freq='D') y = np.linspace(0, 10, 11) da = DataArray( np.random.rand(time.size, y.size), coords=dict(time=time, y=y), dims=('time', 'y') )

import matplotlib.pyplot as plt from matplotlib.dates import date2num, AutoDateFormatter

from https://github.com/pydata/xarray/blob/4da7fdbd85bb82e338ad65a532dd7a9707e18ce0/xarray/plot/plot.py#L1348

def _center_pixels(x): """Center the pixels on the coordinates.""" if np.issubdtype(x.dtype, str): # When using strings as inputs imshow converts it to # integers. Choose extent values which puts the indices in # in the center of the pixels: return 0 - 0.5, len(x) - 0.5

try:
    # Center the pixels assuming uniform spacing:
    xstep = 0.5 * (x[1] - x[0])
except IndexError:
    # Arbitrary default value, similar to matplotlib behaviour:
    xstep = 0.1

return x[0] - xstep, x[-1] + xstep

Center the pixels:

left, right = _center_pixels(da.time) top, bottom = _center_pixels(da.y)

the magical step

vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

left, right = map(date2num, (left, right))

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

plotting

fig, ax = plt.subplots() ax.imshow( da.T, extent=(left, right, top, bottom), origin='lower', aspect='auto' )

ax.xaxis_date() plt.setp(ax.get_xticklabels(), rotation=30, ha='right') ```

MVCE confirmation

• [x] Minimal example — the example is as focused as reasonably possible to demonstrate the underlying issue in xarray.
• [X] Complete example — the example is self-contained, including all data and the text of any traceback.
• [X] Verifiable example — the example copy & pastes into an IPython prompt or Binder notebook, returning the result.
• [X] New issue — a search of GitHub Issues suggests this is not a duplicate.

Relevant log output

```Python

TypeError Traceback (most recent call last) /var/folders/bj/czjbfh496258q1lc3p01lyz00000gn/T/ipykernel_59425/1460104966.py in <module> ----> 1 da.plot.imshow(x='time', y='y')

~/miniconda3/lib/python3.8/site-packages/xarray/plot/plot.py in plotmethod(_PlotMethods_obj, x, y, figsize, size, aspect, ax, row, col, col_wrap, xincrease, yincrease, add_colorbar, add_labels, vmin, vmax, cmap, colors, center, robust, extend, levels, infer_intervals, subplot_kws, cbar_ax, cbar_kwargs, xscale, yscale, xticks, yticks, xlim, ylim, norm, kwargs) 1306 for arg in ["_PlotMethods_obj", "newplotfunc", "kwargs"]: 1307 del allargs[arg] -> 1308 return newplotfunc(allargs) 1309 1310 # Add to class _PlotMethods

~/miniconda3/lib/python3.8/site-packages/xarray/plot/plot.py in newplotfunc(darray, x, y, figsize, size, aspect, ax, row, col, col_wrap, xincrease, yincrease, add_colorbar, add_labels, vmin, vmax, cmap, center, robust, extend, levels, infer_intervals, colors, subplot_kws, cbar_ax, cbar_kwargs, xscale, yscale, xticks, yticks, xlim, ylim, norm, kwargs) 1208 ax = get_axis(figsize, size, aspect, ax, subplot_kws) 1209 -> 1210 primitive = plotfunc( 1211 xplt, 1212 yplt,

~/miniconda3/lib/python3.8/site-packages/xarray/plot/plot.py in imshow(x, y, z, ax, kwargs) 1394 z[np.any(z.mask, axis=-1), -1] = 0 1395 -> 1396 primitive = ax.imshow(z, defaults) 1397 1398 # If x or y are strings the ticklabels have been replaced with

~/miniconda3/lib/python3.8/site-packages/matplotlib/_api/deprecation.py in wrapper(args, kwargs) 454 "parameter will become keyword-only %(removal)s.", 455 name=name, obj_type=f"parameter of {func.name}()") --> 456 return func(args, kwargs) 457 458 # Don't modify func's signature, as boilerplate.py needs it.

~/miniconda3/lib/python3.8/site-packages/matplotlib/init.py in inner(ax, data, args, kwargs) 1410 def inner(ax, args, data=None, kwargs): 1411 if data is None: -> 1412 return func(ax, *map(sanitize_sequence, args), kwargs) 1413 1414 bound = new_sig.bind(ax, args, *kwargs)

~/miniconda3/lib/python3.8/site-packages/matplotlib/axes/_axes.py in imshow(self, X, cmap, norm, aspect, interpolation, alpha, vmin, vmax, origin, extent, interpolation_stage, filternorm, filterrad, resample, url, **kwargs) 5450 # update ax.dataLim, and, if autoscaling, set viewLim 5451 # to tightly fit the image, regardless of dataLim. -> 5452 im.set_extent(im.get_extent()) 5453 5454 self.add_image(im)

~/miniconda3/lib/python3.8/site-packages/matplotlib/image.py in set_extent(self, extent) 980 self._extent = xmin, xmax, ymin, ymax = extent 981 corners = (xmin, ymin), (xmax, ymax) --> 982 self.axes.update_datalim(corners) 983 self.sticky_edges.x[:] = [xmin, xmax] 984 self.sticky_edges.y[:] = [ymin, ymax]

~/miniconda3/lib/python3.8/site-packages/matplotlib/axes/_base.py in update_datalim(self, xys, updatex, updatey) 2474 """ 2475 xys = np.asarray(xys) -> 2476 if not np.any(np.isfinite(xys)): 2477 return 2478 self.dataLim.update_from_data_xy(xys, self.ignore_existing_data_limits,

TypeError: ufunc 'isfinite' not supported for the input types, and the inputs could not be safely coerced to any supported types according to the casting rule ''safe'' ```

Anything else we need to know?

No response

Environment

INSTALLED VERSIONS ------------------ commit: None python: 3.8.12 | packaged by conda-forge | (default, Oct 12 2021, 21:21:17) [Clang 11.1.0 ] python-bits: 64 OS: Darwin OS-release: 21.4.0 machine: arm64 processor: arm byteorder: little LC_ALL: None LANG: None LOCALE: (None, 'UTF-8') libhdf5: 1.12.1 libnetcdf: 4.8.1 xarray: 2022.3.0 pandas: 1.3.4 numpy: 1.21.4 scipy: 1.7.3 netCDF4: 1.5.8 pydap: None h5netcdf: None h5py: None Nio: None zarr: 2.10.3 cftime: 1.6.0 nc_time_axis: 1.4.0 PseudoNetCDF: None rasterio: None cfgrib: 0.9.8.5 iris: None bottleneck: 1.3.2 dask: 2022.04.0 distributed: 2022.4.0 matplotlib: 3.5.0 cartopy: 0.20.2 seaborn: 0.11.2 numbagg: None fsspec: 2022.5.0 cupy: None pint: 0.18 sparse: None setuptools: 62.3.2 pip: 22.1.1 conda: 4.12.0 pytest: None IPython: 7.30.1 sphinx: None