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   "source": [
    "# Street network bearings\n",
    "\n",
    "Author: [Geoff Boeing](https://geoffboeing.com/)\n",
    "\n",
    "Calculate street network bearings and visualize the spatial orientation of a street network. See [this notebook](17-street-network-orientations.ipynb) for a superior example!\n",
    "\n",
    "  - [Overview of OSMnx](http://geoffboeing.com/2016/11/osmnx-python-street-networks/)\n",
    "  - [GitHub repo](https://github.com/gboeing/osmnx)\n",
    "  - [Examples, demos, tutorials](https://github.com/gboeing/osmnx-examples)\n",
    "  - [Documentation](https://osmnx.readthedocs.io/en/stable/)\n",
    "  - [Journal article/citation](http://geoffboeing.com/publications/osmnx-complex-street-networks/)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "import matplotlib.pyplot as plt\n",
    "import osmnx as ox\n",
    "import pandas as pd\n",
    "%matplotlib inline\n",
    "ox.config(log_console=True, use_cache=True)\n",
    "ox.__version__"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### First, look at a non-grid street network\n",
    "\n",
    "Orinda, California is a hilly suburb with winding loops and cul-de-sacs. We can see this lack of consistent orientation in its histogram of edge bearings."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "G = ox.graph_from_place('Orinda, California', network_type='drive')\n",
    "fig, ax = ox.plot_graph(ox.project_graph(G), node_size=0)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# calculate edge bearings and visualize their frequency\n",
    "G = ox.add_edge_bearings(G)\n",
    "bearings = pd.Series([data['bearing'] for u, v, k, data in G.edges(keys=True, data=True)])\n",
    "ax = bearings.hist(bins=30, zorder=2, alpha=0.8)\n",
    "xlim = ax.set_xlim(0, 360)\n",
    "ax.set_title('Orinda street network edge bearings')\n",
    "plt.show()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# polar plot\n",
    "import numpy as np\n",
    "n = 30\n",
    "count, division = np.histogram(bearings, bins=[ang*360/n for ang in range(0,n+1)])\n",
    "division = division[0:-1]\n",
    "width =  2 * np.pi/n\n",
    "ax = plt.subplot(111, projection='polar')\n",
    "ax.set_theta_zero_location('N')\n",
    "ax.set_theta_direction('clockwise')\n",
    "bars = ax.bar(division * np.pi/180 - width * 0.5 , count, width=width, bottom=0.0)\n",
    "ax.set_title('Orinda street network edge bearings', y=1.1)\n",
    "plt.show()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### Now look at a gridded street network\n",
    "\n",
    "Santa Monica has an orthogonal grid characterized by four-way intersections. We can see this clear orientation in its histogram of edge bearings."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "G = ox.graph_from_place('Santa Monica, California', network_type='drive')\n",
    "fig, ax = ox.plot_graph(ox.project_graph(G), node_size=0)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# calculate edge bearings and visualize their frequency\n",
    "G = ox.add_edge_bearings(G)\n",
    "bearings = pd.Series([data['bearing'] for u, v, k, data in G.edges(keys=True, data=True)])\n",
    "ax = bearings.hist(bins=30, zorder=2, alpha=0.8)\n",
    "ax.set_xlim(0, 360)\n",
    "ax.set_title('Santa Monica street network edge bearings')\n",
    "plt.show()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# polar plot\n",
    "n = 30\n",
    "count, division = np.histogram(bearings, bins=[ang*360/n for ang in range(0,n+1)])\n",
    "division = division[0:-1]\n",
    "width =  2 * np.pi/n\n",
    "ax = plt.subplot(111, projection='polar')\n",
    "ax.set_theta_zero_location('N')\n",
    "ax.set_theta_direction('clockwise')\n",
    "bars = ax.bar(division * np.pi/180 - width * 0.5 , count, width=width, bottom=20.0)\n",
    "ax.set_title('Santa Monica street network edge bearings', y=1.1)\n",
    "plt.show()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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