{
  "cells": [
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "\n\n# Editing network geometry: Splitting link\n\nIn this example, we split a link right in the middle, while keeping all fields\nin the database equal. Distance is proportionally computed automatically in the database.\n"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "Imports\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "from uuid import uuid4\nfrom tempfile import gettempdir\nfrom os.path import join\nfrom aequilibrae.utils.create_example import create_example\nfrom shapely.ops import substring\nimport matplotlib.pyplot as plt\n\n# We create the example project inside our temp folder\nfldr = join(gettempdir(), uuid4().hex)\n\nproject = create_example(fldr)"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "We will split link 37 right in the middle\nLet's get the link and check its length\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "links = project.network.links\nall_nodes = project.network.nodes\n\nlink = links.get(37)\nprint(link.distance)"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "The idea is basically to copy a link and allocate the appropriate geometries\nto split the geometry we use Shapely's substring\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "new_link = links.copy_link(37)\n\nfirst_geometry = substring(link.geometry, 0, 0.5, normalized=True)\nsecond_geometry = substring(link.geometry, 0.5, 1, normalized=True)\n\nlink.geometry = first_geometry\nnew_link.geometry = second_geometry\nlinks.save()"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "The link objects in memory still don't have their ID fields updated, so we refresh them\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "links.refresh()\nlink = links.get(37)\nnew_link = links.get(new_link.link_id)\nprint(link.distance, new_link.distance)"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "We can plot the two links only\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "plt.clf()\nplt.plot(*link.geometry.xy, color=\"blue\")\nplt.plot(*new_link.geometry.xy, color=\"blue\")\n\nfor node in [link.a_node, link.b_node, new_link.b_node]:\n    geo = all_nodes.get(node).geometry\n    plt.plot(*geo.xy, \"o\", color=\"black\")\nplt.show()"
      ]
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "Or we plot the entire network\n\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "plt.clf()\ncurr = project.conn.cursor()\ncurr.execute(\"Select link_id from links;\")\n\nfor lid in curr.fetchall():\n    geo = links.get(lid[0]).geometry\n    plt.plot(*geo.xy, color=\"blue\")\n\nall_nodes = project.network.nodes\ncurr = project.conn.cursor()\ncurr.execute(\"Select node_id from nodes;\")\n\nfor nid in curr.fetchall():\n    geo = all_nodes.get(nid[0]).geometry\n    plt.plot(*geo.xy, \"o\", color=\"black\")\n\nplt.show()"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
        "collapsed": false
      },
      "outputs": [],
      "source": [
        "project.close()"
      ]
    }
  ],
  "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": "3.9.18"
    }
  },
  "nbformat": 4,
  "nbformat_minor": 0
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