GridInterface bin support for Histogram and QuadMesh

examples/gallery/demos/bokeh/irregular_quadmesh.ipynb

@@ -0,0 +1,84 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Most examples work across multiple plotting backends, this example is also available for:\n",
+    "\n",
+    "* [Matplotlib irregular_quadmesh](../matplotlib/irregular_quadmesh.ipynb)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import numpy as np\n",
+    "import holoviews as hv\n",
+    "hv.extension('bokeh')"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Declaring data"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "n = 20\n",
+    "coords = np.linspace(-1.5, 1.5, n)\n",
+    "X,Y = np.meshgrid(coords, coords);\n",
+    "Qx = np.cos(Y) - np.cos(X)\n",
+    "Qz = np.sin(Y) + np.sin(X)\n",
+    "Z = np.sqrt(X**2 + Y**2)\n",
+    "\n",
+    "qmesh = hv.QuadMesh((Qx, Qz, Z))"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Plot"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "qmesh"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.6.3"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 2
+}

examples/gallery/demos/matplotlib/irregular_quadmesh.ipynb

@@ -0,0 +1,85 @@
+{
+ "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "Most examples work across multiple plotting backends, this example is also available for:\n",
+    "\n",
+    "* [Bokeh irregular_quadmesh](../bokeh/irregular_quadmesh.ipynb)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import numpy as np\n",
+    "import holoviews as hv\n",
+    "hv.extension('matplotlib')\n",
+    "%output fig='svg'"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Declaring data\n"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "n = 20\n",
+    "coords = np.linspace(-1.5, 1.5, n)\n",
+    "X,Y = np.meshgrid(coords, coords);\n",
+    "Qx = np.cos(Y) - np.cos(X)\n",
+    "Qz = np.sin(Y) + np.sin(X)\n",
+    "Z = np.sqrt(X**2 + Y**2)\n",
+    "\n",
+    "qmesh = hv.QuadMesh((Qx, Qz, Z))"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Plot"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "qmesh"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.6.3"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 2
+}

examples/reference/elements/bokeh/QuadMesh.ipynb

@@ -41,6 +41,9 @@
     "xs = np.logspace(1, 3, n)\n",
     "ys = np.linspace(1, 10, n)\n",
     "zs = np.arange((n-1)**2).reshape(n-1, n-1)\n",
+    "print('Shape of x-coordinates:', xs.shape)\n",
+    "print('Shape of y-coordinates:', ys.shape)\n",
+    "print('Shape of value array:', zs.shape)\n",
     "hv.QuadMesh((xs, ys, zs))"
    ]
   },
@@ -106,12 +109,77 @@
     "\n",
     "For full documentation and the available style and plot options, use ``hv.help(hv.QuadMesh).``"
    ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Irregular meshes\n",
+    "\n",
+    "In addition to axis aligned meshes like those we worked with above, a ``QuadMesh`` may also be used to represent irregular or unstructured meshes. In this example we will create an irregular mesh consisting of 2D X, Y and Z arrays defining the position and value of each simplex in the mesh:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "n=20\n",
+    "coords = np.linspace(-1.5,1.5,n)\n",
+    "X,Y = np.meshgrid(coords, coords);\n",
+    "Qx = np.cos(Y) - np.cos(X)\n",
+    "Qy = np.sin(Y) + np.sin(X)\n",
+    "Z = np.sqrt(X**2 + Y**2)\n",
+    "\n",
+    "print('Shape of x-coordinates:', Qx.shape)\n",
+    "print('Shape of y-coordinates:', Qy.shape)\n",
+    "print('Shape of value array:', Z.shape)\n",
+    "\n",
+    "qmesh = hv.QuadMesh((Qx, Qy, Z))\n",
+    "qmesh"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "To illustrate irregular meshes a bit further we will randomly jitter the mesh coordinates along both dimensions, demonstrating that ``QuadMesh`` may be used to represent completely arbitrary meshes. It may also be used to represent overlapping meshes, however the behavior during slicing and other operations may not be well defined in such cases."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "np.random.seed(13)\n",
+    "xs, ys = np.meshgrid(np.linspace(-20, 20, 10), np.linspace(0, 30, 8))\n",
+    "xs += xs/10 + np.random.rand(*xs.shape)*4\n",
+    "ys += ys/10 + np.random.rand(*ys.shape)*4\n",
+    "\n",
+    "zs = np.arange(80).reshape(8, 10)\n",
+    "hv.QuadMesh((xs, ys, zs))"
+   ]
   }
  ],
  "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
   "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
    "name": "python",
-   "pygments_lexer": "ipython3"
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.6.3"
   }
  },
  "nbformat": 4,

examples/reference/elements/matplotlib/QuadMesh.ipynb

@@ -41,6 +41,9 @@
     "xs = np.logspace(1, 3, n)\n",
     "ys = np.linspace(1, 10, n)\n",
     "zs = np.arange((n-1)**2).reshape(n-1, n-1)\n",
+    "print('Shape of x-coordinates:', xs.shape)\n",
+    "print('Shape of y-coordinates:', ys.shape)\n",
+    "print('Shape of value array:', zs.shape)\n",
     "hv.QuadMesh((xs, ys, zs))"
    ]
   },
@@ -88,12 +91,77 @@
     "\n",
     "For full documentation and the available style and plot options, use ``hv.help(hv.QuadMesh).``"
    ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "## Irregular meshes\n",
+    "\n",
+    "In addition to axis aligned meshes like those we worked with above, a ``QuadMesh`` may also be used to represent irregular or unstructured meshes. In this example we will create an irregular mesh consisting of 2D X, Y and Z arrays defining the position and value of each simplex in the mesh:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "n=20\n",
+    "coords = np.linspace(-1.5,1.5,n)\n",
+    "X,Y = np.meshgrid(coords, coords);\n",
+    "Qx = np.cos(Y) - np.cos(X)\n",
+    "Qy = np.sin(Y) + np.sin(X)\n",
+    "Z = np.sqrt(X**2 + Y**2)\n",
+    "\n",
+    "print('Shape of x-coordinates:', Qx.shape)\n",
+    "print('Shape of y-coordinates:', Qy.shape)\n",
+    "print('Shape of value array:', Z.shape)\n",
+    "\n",
+    "qmesh = hv.QuadMesh((Qx, Qy, Z))\n",
+    "qmesh"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "To illustrate irregular meshes a bit further we will randomly jitter the mesh coordinates along both dimensions, demonstrating that ``QuadMesh`` may be used to represent completely arbitrary meshes. It may also be used to represent overlapping meshes, however the behavior during slicing and other operations may not be well defined in such cases."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "np.random.seed(13)\n",
+    "xs, ys = np.meshgrid(np.linspace(-20, 20, 10), np.linspace(0, 30, 8))\n",
+    "xs += xs/10 + np.random.rand(*xs.shape)*4\n",
+    "ys += ys/10 + np.random.rand(*ys.shape)*4\n",
+    "\n",
+    "zs = np.arange(80).reshape(8, 10)\n",
+    "hv.QuadMesh((xs, ys, zs))"
+   ]
   }
  ],
  "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
   "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
    "name": "python",
-   "pygments_lexer": "ipython3"
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.6.3"
   }
  },
  "nbformat": 4,

holoviews/core/data/__init__.py

@@ -175,6 +175,9 @@ class Dataset(Element):
     # Define a class used to transform Datasets into other Element types
     _conversion_interface = DataConversion
 
+    # Whether the key dimensions are specified as bins
+    _binned = False
+
     _vdim_reductions = {}
     _kdim_reductions = {}
 
@@ -361,7 +364,7 @@ def __getitem__(self, slices):
             value_select = slices[self.ndims]
         elif len(slices) == self.ndims+1 and isinstance(slices[self.ndims],
                                                         (Dimension,str)):
-            raise Exception("%r is not an available value dimension" % slices[self.ndims])
+            raise IndexError("%r is not an available value dimension" % slices[self.ndims])
         else:
             selection = dict(zip(self.dimensions(label=True), slices))
         data = self.select(**selection)

holoviews/core/data/array.py

@@ -41,7 +41,9 @@ def init(cls, eltype, data, kdims, vdims):
                             for k, v in dict_data))
             data = np.column_stack(dataset)
         elif isinstance(data, tuple):
-            data = [d if isinstance(d, np.ndarray) else np.array(d) for d in data]
+            data = [np.asarray(d) for d in data]
+            if any(arr.ndim > 1 for arr in data):
+                raise ValueError('ArrayInterface expects data to be of flat shape.')
             if cls.expanded(data):
                 data = np.column_stack(data)
             else:

holoviews/core/data/dictionary.py

@@ -95,7 +95,10 @@ def init(cls, eltype, data, kdims, vdims):
                     for i, sd in enumerate(d):
                         unpacked.append((sd, vals[:, i]))
                 else:
-                    unpacked.append((d, vals if np.isscalar(vals) else np.asarray(vals)))
+                    vals = vals if np.isscalar(vals) else np.asarray(vals)
+                    if not np.isscalar(vals) and not vals.ndim == 1:
+                        raise ValueError('DictInterface expects data for each column to be flat.')
+                    unpacked.append((d, vals))
             if not cls.expanded([d[1] for d in unpacked if not np.isscalar(d[1])]):
                 raise ValueError('DictInterface expects data to be of uniform shape.')
             if isinstance(data, odict_types):