diff --git a/doc/whats-new.rst b/doc/whats-new.rst
index 47e2e58e988..30b167ebfdc 100644
--- a/doc/whats-new.rst
+++ b/doc/whats-new.rst
@@ -76,6 +76,9 @@ Bug fixes
:py:meth:`xarray.core.groupby.DatasetGroupBy.reduce` when reducing over multiple dimensions.
(:issue:`3402`). By `Deepak Cherian `_
+- Fix plotting with transposed 2D non-dimensional coordinates. (:issue:`3138`)
+ By `Deepak Cherian `_.
+
Documentation
~~~~~~~~~~~~~
- Fix leap year condition in example (http://xarray.pydata.org/en/stable/examples/monthly-means.html) by `Mickaƫl Lalande `_.
diff --git a/xarray/plot/plot.py b/xarray/plot/plot.py
index ca68f617144..c6bb231ce17 100644
--- a/xarray/plot/plot.py
+++ b/xarray/plot/plot.py
@@ -672,10 +672,16 @@ def newplotfunc(
# check if we need to broadcast one dimension
if xval.ndim < yval.ndim:
- xval = np.broadcast_to(xval, yval.shape)
+ if xval.shape[0] == yval.shape[0]:
+ xval = np.broadcast_to(xval[:, np.newaxis], yval.shape)
+ else:
+ xval = np.broadcast_to(xval[np.newaxis, :], yval.shape)
- if yval.ndim < xval.ndim:
- yval = np.broadcast_to(yval, xval.shape)
+ elif yval.ndim < xval.ndim:
+ if yval.shape[0] == xval.shape[0]:
+ yval = np.broadcast_to(yval[:, np.newaxis], xval.shape)
+ else:
+ yval = np.broadcast_to(yval[np.newaxis, :], xval.shape)
# May need to transpose for correct x, y labels
# xlab may be the name of a coord, we have to check for dim names
@@ -687,7 +693,7 @@ def newplotfunc(
dims = yx_dims + tuple(d for d in darray.dims if d not in yx_dims)
if dims != darray.dims:
darray = darray.transpose(*dims, transpose_coords=True)
- elif darray[xlab].dims[-1] == darray.dims[0]:
+ elif xval.shape[-1] == darray.shape[0]:
darray = darray.transpose(transpose_coords=True)
# Pass the data as a masked ndarray too
diff --git a/xarray/tests/test_plot.py b/xarray/tests/test_plot.py
index 7deabd46eae..58210e6ffa0 100644
--- a/xarray/tests/test_plot.py
+++ b/xarray/tests/test_plot.py
@@ -2145,3 +2145,19 @@ def test_yticks_kwarg(self, da):
da.plot(yticks=np.arange(5))
expected = np.arange(5)
assert np.all(plt.gca().get_yticks() == expected)
+
+
+@requires_matplotlib
+@pytest.mark.parametrize("plotfunc", ["pcolormesh", "contourf", "contour"])
+def test_plot_transposed_nondim_coord(plotfunc):
+ x = np.linspace(0, 10, 101)
+ h = np.linspace(3, 7, 101)
+ s = np.linspace(0, 1, 51)
+ z = s[:, np.newaxis] * h[np.newaxis, :]
+ da = xr.DataArray(
+ np.sin(x) * np.cos(z),
+ dims=["s", "x"],
+ coords={"x": x, "s": s, "z": (("s", "x"), z), "zt": (("x", "s"), z.T)},
+ )
+ getattr(da.plot, plotfunc)(x="x", y="zt")
+ getattr(da.plot, plotfunc)(x="zt", y="x")