Allow plotting partially irregular QuadMesh

holoviews/core/util.py

@@ -1819,10 +1819,27 @@ def expand_grid_coords(dataset, dim):
     dataset into an ND-array matching the dimensionality of
     the dataset.
     """
-    arrays = [dataset.interface.coords(dataset, d.name, True)
-              for d in dataset.kdims]
-    idx = dataset.get_dimension_index(dim)
-    return cartesian_product(arrays, flat=False)[idx].T
+    irregular = [d.name for d in dataset.kdims
+                 if d is not dim and dataset.interface.irregular(dataset, d)]
+    if irregular:
+        array = dataset.interface.coords(dataset, dim, True)
+        example = dataset.interface.values(dataset, irregular[0], True, False)
+        if dataset.interface.datatype == 'xarray':
+            index = dataset.data[irregular[0]].dims.index(dim)
+        else:
+            index = (example.ndim - dataset.get_dimension_index(dim) - 1)
+        shape = list(example.shape)
+        n = shape.pop(index)
+        coords = np.broadcast_to(array, tuple(shape)+(n,))
+        inds = list(range(dataset.ndims))
+        inds[index] = dataset.ndims-1
+        inds[-1] = index
+        return coords.transpose(tuple(inds))
+    else:
+        arrays = [dataset.interface.coords(dataset, d.name, True)
+                  for d in dataset.kdims]
+        idx = dataset.get_dimension_index(dim)
+        return cartesian_product(arrays, flat=False)[idx].T
 
 
 def dt64_to_dt(dt64):

holoviews/plotting/bokeh/raster.py

@@ -207,7 +207,8 @@ def get_data(self, element, ranges, style):
         cmapper = self._get_colormapper(z, element, ranges, style)
         cmapper = {'field': z.name, 'transform': cmapper}
 
-        irregular = element.interface.irregular(element, x)
+        irregular = (element.interface.irregular(element, x) or
+                     element.interface.irregular(element, y))
         if irregular:
             mapping = dict(xs='xs', ys='ys', fill_color=cmapper)
         else: