{
 "cells": [
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "from matplotlib import pyplot\n",
    "from shapely.geometry.polygon import LinearRing\n",
    "\n",
    "%matplotlib inline"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "COLOR = {\n",
    "    True:  '#6699cc',\n",
    "    False: '#ff3333'\n",
    "    }\n",
    "\n",
    "def v_color(ob):\n",
    "    return COLOR[ob.is_valid]\n",
    "\n",
    "def plot_coords(ax, ob):\n",
    "    x, y = ob.xy\n",
    "    ax.plot(x, y, 'o', color='#999999', zorder=1)\n",
    "\n",
    "def plot_line(ax, ob):\n",
    "    x, y = ob.xy\n",
    "    ax.plot(x, y, color=v_color(ob), alpha=0.7, linewidth=3, solid_capstyle='round', zorder=2)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "\n",
    "fig = pyplot.figure(1, figsize=(12,20), dpi=90)\n",
    "\n",
    "# 1: valid ring\n",
    "ax = fig.add_subplot(121)\n",
    "ring = LinearRing([(0, 0), (0, 2), (1, 1), (2, 2), (2, 0), (1, 0.8), (0, 0)])\n",
    "\n",
    "plot_coords(ax, ring)\n",
    "plot_line(ax, ring)\n",
    "\n",
    "ax.set_title('a) valid')\n",
    "\n",
    "xrange = [-1, 3]\n",
    "yrange = [-1, 3]\n",
    "ax.set_xlim(*xrange)\n",
    "ax.set_xticks([-1, 0, 1, 2, 3])\n",
    "ax.set_ylim(*yrange)\n",
    "ax.set_yticks([-1, 0, 1, 2, 3])\n",
    "ax.set_aspect(1)\n",
    "\n",
    "#2: invalid self-touching ring\n",
    "ax = fig.add_subplot(122)\n",
    "ring2 = LinearRing([(0, 0), (0, 2), (1, 1), (2, 2), (2, 0), (1, 1), (0, 0)])\n",
    "\n",
    "plot_coords(ax, ring2)\n",
    "plot_line(ax, ring2)\n",
    "\n",
    "ax.set_title('b) invalid')\n",
    "\n",
    "xrange = [-1, 3]\n",
    "yrange = [-1, 3]\n",
    "ax.set_xlim(*xrange)\n",
    "ax.set_xticks([-1, 0, 1, 2, 3])\n",
    "ax.set_ylim(*yrange)\n",
    "ax.set_yticks([-1, 0, 1, 2, 3])\n",
    "ax.set_aspect(1)\n",
    "\n",
    "pyplot.show()\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
 ],
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