محاذاة إلى الطرق

تتلقّى Roads API ما يصل إلى 100 نقطة GPS تم جمعها على طول مسار معيّن، وتُعرِض مجموعة بيانات مشابهة، مع تثبيت النقاط على الطرق الأكثر احتمالًا التي كانت المركبة تسير عليها. اختياريًا، يمكنك طلب استقراء النقاط، مما ينتج عنه مسار يتبع هندسة الطريق.

الطلبات

يجب إرسال طلب المحاذاة إلى الطريق عبر HTTPS، وأن يكون بالشكل التالي:

https://roads.googleapis.com/v1/snapToRoads?parameters&key=YOUR_API_KEY

Required parameters

  • path

    The path to be snapped. The path parameter accepts a list of latitude/longitude pairs. Latitude and longitude values should be separated by commas. Coordinates should be separated by the pipe character: "|". For example: path=60.170880,24.942795|60.170879,24.942796|60.170877,24.942796.

    Note: The snapping algorithm works best for points that are not too far apart. If you observe odd snapping behavior, try creating paths that have points closer together. To ensure the best snap-to-road quality, you should aim to provide paths on which consecutive pairs of points are within 300m of each other. This will also help in handling any isolated, long jumps between consecutive points caused by GPS signal loss, or noise.

Optional parameters

  • interpolate

    Whether to interpolate a path to include all points forming the full road-geometry. When true, additional interpolated points will also be returned, resulting in a path that smoothly follows the geometry of the road, even around corners and through tunnels. Interpolated paths will most likely contain more points than the original path. Defaults to false.

أمثلة

سيؤدي الطلب التالي إلى ربط النقاط المحدّدة بأشكال الطريق. هذا النمط مجموعة معينة من البيانات تتبع طريقًا دائريًا؛ إعداد "interpolate=true" تأكد من تطابق الهندسة المعروضة مع انحناء الطريق. مع interpolate=false، سيظل المسار المقطوع يتبع الطريق، ولكن لن يكون الخط المتعدد الناتج سلسًا.

عنوان URL

https://roads.googleapis.com/v1/snapToRoads
  ?interpolate=true
  &path=-35.27801%2C149.12958%7C-35.28032%2C149.12907%7C-35.28099%2C149.12929%7C-35.28144%2C149.12984%7C-35.28194%2C149.13003%7C-35.28282%2C149.12956%7C-35.28302%2C149.12881%7C-35.28473%2C149.12836
  &key=YOUR_API_KEY

cURL

curl -L -X GET 'https://roads.googleapis.com/v1/snapToRoads?path=-35.27801%2C149.12958%7C-35.28032%2C149.12907%7C-35.28099%2C149.12929%7C-35.28144%2C149.12984%7C-35.28194%2C149.13003%7C-35.28282%2C149.12956%7C-35.28302%2C149.12881%7C-35.28473%2C149.12836&interpolate=true&key=YOUR_API_KEY'

الردود

لكل طلب صالح، ستعرض Roads API ردًا في المشار إليه في عنوان URL للطلب مثل استجابة JSON التالية.

{
  "snappedPoints":
    [
      {
        "location":
          { "latitude": -35.27800489993019, "longitude": 149.129531998742 },
        "originalIndex": 0,
        "placeId": "ChIJr_xl0GdNFmsRsUtUbW7qABM",
      },
      {
        "location":
          { "latitude": -35.2784195, "longitude": 149.12946589999999 },
        "placeId": "ChIJr_xl0GdNFmsRsUtUbW7qABM",
      },
      {
        "location":
          { "latitude": -35.2784195, "longitude": 149.12946589999999 },
        "placeId": "ChIJ6aXGemhNFmsRZE_zHqhmrG4",
      },
      {
        "location":
          { "latitude": -35.2792731, "longitude": 149.12933809999998 },
        "placeId": "ChIJ6aXGemhNFmsRZE_zHqhmrG4",
      },
      {
        "location":
          { "latitude": -35.2792731, "longitude": 149.12933809999998 },
        "placeId": "ChIJTcTdZ2hNFmsRXokM4mWCWfk",
      },
      {
        "location": { "latitude": -35.279557, "longitude": 149.1292973 },
        "placeId": "ChIJTcTdZ2hNFmsRXokM4mWCWfk",
      },
      {
        "location": { "latitude": -35.279557, "longitude": 149.1292973 },
        "placeId": "ChIJiUfNQmhNFmsRSsAI-1m6y1g",
      },
      {
        "location":
          { "latitude": -35.279610999999996, "longitude": 149.1292889 },
        "placeId": "ChIJiUfNQmhNFmsRSsAI-1m6y1g",
      },
      {
        "location": { "latitude": -35.2796484, "longitude": 149.1292791 },
        "placeId": "ChIJiUfNQmhNFmsRSsAI-1m6y1g",
      },
      {
        "location": { "latitude": -35.2796484, "longitude": 149.1292791 },
        "placeId": "ChIJ_RyFQ2hNFmsRoHJAbW7qABM",
      },
      {
        "location":
          { "latitude": -35.279947299999996, "longitude": 149.1291894 },
        "placeId": "ChIJ_RyFQ2hNFmsRoHJAbW7qABM",
      },
      {
        "location":
          { "latitude": -35.279947299999996, "longitude": 149.1291894 },
        "placeId": "ChIJOyypT2hNFmsRZBtscGL0htw",
      },
      {
        "location":
          { "latitude": -35.280323564795005, "longitude": 149.1290903128365 },
        "originalIndex": 1,
        "placeId": "ChIJOyypT2hNFmsRZBtscGL0htw",
      },
      {
        "location":
          { "latitude": -35.2803426, "longitude": 149.12908529999999 },
        "placeId": "ChIJOyypT2hNFmsRZBtscGL0htw",
      },
      {
        "location":
          { "latitude": -35.2803426, "longitude": 149.12908529999999 },
        "placeId": "ChIJr8xRTGhNFmsRzMb-rxgjspc",
      },
      {
        "location":
          { "latitude": -35.280409899999995, "longitude": 149.1290699 },
        "placeId": "ChIJr8xRTGhNFmsRzMb-rxgjspc",
      },
      {
        "location": { "latitude": -35.28048179999999, "longitude": 149.129062 },
        "placeId": "ChIJr8xRTGhNFmsRzMb-rxgjspc",
      },
      {
        "location": { "latitude": -35.2805541, "longitude": 149.1290623 },
        "placeId": "ChIJr8xRTGhNFmsRzMb-rxgjspc",
      },
      {
        "location": { "latitude": -35.280626, "longitude": 149.1290712 },
        "placeId": "ChIJr8xRTGhNFmsRzMb-rxgjspc",
      },
      {
        "location": { "latitude": -35.280626, "longitude": 149.1290712 },
        "placeId": "ChIJv5r0smlNFmsR5nunau79Fv4",
      },
      {
        "location":
          { "latitude": -35.280695099999996, "longitude": 149.12908489999998 },
        "placeId": "ChIJv5r0smlNFmsR5nunau79Fv4",
      },
      {
        "location": { "latitude": -35.2807629, "longitude": 149.1291046 },
        "placeId": "ChIJv5r0smlNFmsR5nunau79Fv4",
      },
      {
        "location": { "latitude": -35.2808294, "longitude": 149.1291306 },
        "placeId": "ChIJv5r0smlNFmsR5nunau79Fv4",
      },
      {
        "location": { "latitude": -35.2809064, "longitude": 149.1291693 },
        "placeId": "ChIJv5r0smlNFmsR5nunau79Fv4",
      },
      {
        "location":
          { "latitude": -35.280968200000004, "longitude": 149.129208 },
        "placeId": "ChIJv5r0smlNFmsR5nunau79Fv4",
      },
      {
        "location":
          { "latitude": -35.28101395754623, "longitude": 149.1292430025548 },
        "originalIndex": 2,
        "placeId": "ChIJv5r0smlNFmsR5nunau79Fv4",
      },
      {
        "location":
          { "latitude": -35.28103840000001, "longitude": 149.1292617 },
        "placeId": "ChIJv5r0smlNFmsR5nunau79Fv4",
      },
      {
        "location": { "latitude": -35.2810936, "longitude": 149.1293121 },
        "placeId": "ChIJv5r0smlNFmsR5nunau79Fv4",
      },
      {
        "location": { "latitude": -35.2810979, "longitude": 149.1293176 },
        "placeId": "ChIJv5r0smlNFmsR5nunau79Fv4",
      },
      {
        "location": { "latitude": -35.2810979, "longitude": 149.1293176 },
        "placeId": "ChIJpYMSrmlNFmsRXkCoIkZxgBg",
      },
      {
        "location":
          { "latitude": -35.281152399999996, "longitude": 149.1294256 },
        "placeId": "ChIJpYMSrmlNFmsRXkCoIkZxgBg",
      },
      {
        "location":
          { "latitude": -35.281152399999996, "longitude": 149.1294256 },
        "placeId": "ChIJ601MoWlNFmsR5mvkfPp2ovA",
      },
      {
        "location": { "latitude": -35.2811784, "longitude": 149.1294706 },
        "placeId": "ChIJ601MoWlNFmsR5mvkfPp2ovA",
      },
      {
        "location": { "latitude": -35.2812258, "longitude": 149.1295413 },
        "placeId": "ChIJ601MoWlNFmsR5mvkfPp2ovA",
      },
      {
        "location":
          { "latitude": -35.2812771, "longitude": 149.12960759999999 },
        "placeId": "ChIJ601MoWlNFmsR5mvkfPp2ovA",
      },
      {
        "location": { "latitude": -35.281332, "longitude": 149.1296695 },
        "placeId": "ChIJ601MoWlNFmsR5mvkfPp2ovA",
      },
      {
        "location":
          { "latitude": -35.2813904, "longitude": 149.12972670000002 },
        "placeId": "ChIJ601MoWlNFmsR5mvkfPp2ovA",
      },
      {
        "location":
          { "latitude": -35.281451700000005, "longitude": 149.1297788 },
        "placeId": "ChIJ601MoWlNFmsR5mvkfPp2ovA",
      },
      {
        "location":
          { "latitude": -35.28146506991143, "longitude": 149.12978858234607 },
        "originalIndex": 3,
        "placeId": "ChIJ601MoWlNFmsR5mvkfPp2ovA",
      },
      {
        "location":
          { "latitude": -35.28151580000001, "longitude": 149.1298257 },
        "placeId": "ChIJ601MoWlNFmsR5mvkfPp2ovA",
      },
      {
        "location": { "latitude": -35.28158259999999, "longitude": 149.129867 },
        "placeId": "ChIJ601MoWlNFmsR5mvkfPp2ovA",
      },
      {
        "location":
          { "latitude": -35.281666099999995, "longitude": 149.1299091 },
        "placeId": "ChIJ601MoWlNFmsR5mvkfPp2ovA",
      },
      {
        "location": { "latitude": -35.2817377, "longitude": 149.1299379 },
        "placeId": "ChIJ601MoWlNFmsR5mvkfPp2ovA",
      },
      {
        "location":
          { "latitude": -35.281810899999996, "longitude": 149.1299602 },
        "placeId": "ChIJ601MoWlNFmsR5mvkfPp2ovA",
      },
      {
        "location":
          { "latitude": -35.281884999999996, "longitude": 149.1299765 },
        "placeId": "ChIJ601MoWlNFmsR5mvkfPp2ovA",
      },
      {
        "location":
          { "latitude": -35.28194399606459, "longitude": 149.1299842294294 },
        "originalIndex": 4,
        "placeId": "ChIJ601MoWlNFmsR5mvkfPp2ovA",
      },
      {
        "location":
          { "latitude": -35.281959799999996, "longitude": 149.12998629999998 },
        "placeId": "ChIJ601MoWlNFmsR5mvkfPp2ovA",
      },
      {
        "location":
          { "latitude": -35.282035199999996, "longitude": 149.1299895 },
        "placeId": "ChIJ601MoWlNFmsR5mvkfPp2ovA",
      },
      {
        "location": { "latitude": -35.2821254, "longitude": 149.1299851 },
        "placeId": "ChIJ601MoWlNFmsR5mvkfPp2ovA",
      },
      {
        "location":
          { "latitude": -35.282199999999996, "longitude": 149.1299743 },
        "placeId": "ChIJ601MoWlNFmsR5mvkfPp2ovA",
      },
      {
        "location": { "latitude": -35.2822739, "longitude": 149.1299573 },
        "placeId": "ChIJ601MoWlNFmsR5mvkfPp2ovA",
      },
      {
        "location": { "latitude": -35.2823468, "longitude": 149.129934 },
        "placeId": "ChIJ601MoWlNFmsR5mvkfPp2ovA",
      },
      {
        "location": { "latitude": -35.2824178, "longitude": 149.1299043 },
        "placeId": "ChIJ601MoWlNFmsR5mvkfPp2ovA",
      },
      {
        "location": { "latitude": -35.2824379, "longitude": 149.1298945 },
        "placeId": "ChIJ601MoWlNFmsR5mvkfPp2ovA",
      },
      {
        "location": { "latitude": -35.2824379, "longitude": 149.1298945 },
        "placeId": "ChIJe9LPnWlNFmsR7mJw8mYHwG0",
      },
      {
        "location":
          { "latitude": -35.282472999999996, "longitude": 149.1298835 },
        "placeId": "ChIJe9LPnWlNFmsR7mJw8mYHwG0",
      },
      {
        "location": { "latitude": -35.2825375, "longitude": 149.1298525 },
        "placeId": "ChIJe9LPnWlNFmsR7mJw8mYHwG0",
      },
      {
        "location":
          { "latitude": -35.28257309999999, "longitude": 149.1298319 },
        "placeId": "ChIJe9LPnWlNFmsR7mJw8mYHwG0",
      },
      {
        "location":
          { "latitude": -35.28257309999999, "longitude": 149.1298319 },
        "placeId": "ChIJaUpThGlNFmsRMHWxoH7EOsc",
      },
      {
        "location":
          { "latitude": -35.282665400000006, "longitude": 149.12974459999998 },
        "placeId": "ChIJaUpThGlNFmsRMHWxoH7EOsc",
      },
      {
        "location":
          { "latitude": -35.28274030000001, "longitude": 149.1296645 },
        "placeId": "ChIJaUpThGlNFmsRMHWxoH7EOsc",
      },
      {
        "location":
          { "latitude": -35.282809799999995, "longitude": 149.12957799999998 },
        "placeId": "ChIJaUpThGlNFmsRMHWxoH7EOsc",
      },
      {
        "location":
          { "latitude": -35.28282136229385, "longitude": 149.12956142620385 },
        "originalIndex": 5,
        "placeId": "ChIJaUpThGlNFmsRMHWxoH7EOsc",
      },
      {
        "location": { "latitude": -35.2828744, "longitude": 149.1294854 },
        "placeId": "ChIJaUpThGlNFmsRMHWxoH7EOsc",
      },
      {
        "location":
          { "latitude": -35.282922299999996, "longitude": 149.1294044 },
        "placeId": "ChIJaUpThGlNFmsRMHWxoH7EOsc",
      },
      {
        "location":
          { "latitude": -35.282931500000004, "longitude": 149.1293876 },
        "placeId": "ChIJaUpThGlNFmsRMHWxoH7EOsc",
      },
      {
        "location": { "latitude": -35.2830263, "longitude": 149.1291788 },
        "placeId": "ChIJaUpThGlNFmsRMHWxoH7EOsc",
      },
      {
        "location": { "latitude": -35.2830263, "longitude": 149.1291788 },
        "placeId": "ChIJyd3JiWlNFmsR9RUq2ySTTZQ",
      },
      {
        "location": { "latitude": -35.283054, "longitude": 149.1290996 },
        "placeId": "ChIJyd3JiWlNFmsR9RUq2ySTTZQ",
      },
      {
        "location": { "latitude": -35.2830794, "longitude": 149.1290094 },
        "placeId": "ChIJyd3JiWlNFmsR9RUq2ySTTZQ",
      },
      {
        "location": { "latitude": -35.2830794, "longitude": 149.1290094 },
        "placeId": "ChIJWSb8ImpNFmsRp_4JAxJFE1A",
      },
      {
        "location":
          { "latitude": -35.28313383700836, "longitude": 149.12893500604946 },
        "originalIndex": 6,
        "placeId": "ChIJWSb8ImpNFmsRp_4JAxJFE1A",
      },
      {
        "location":
          { "latitude": -35.283134499999996, "longitude": 149.12893409999998 },
        "placeId": "ChIJWSb8ImpNFmsRp_4JAxJFE1A",
      },
      {
        "location":
          { "latitude": -35.283190399999995, "longitude": 149.1288668 },
        "placeId": "ChIJWSb8ImpNFmsRp_4JAxJFE1A",
      },
      {
        "location": { "latitude": -35.2832503, "longitude": 149.1288041 },
        "placeId": "ChIJWSb8ImpNFmsRp_4JAxJFE1A",
      },
      {
        "location": { "latitude": -35.2833133, "longitude": 149.1287463 },
        "placeId": "ChIJWSb8ImpNFmsRp_4JAxJFE1A",
      },
      {
        "location": { "latitude": -35.2833794, "longitude": 149.128694 },
        "placeId": "ChIJWSb8ImpNFmsRp_4JAxJFE1A",
      },
      {
        "location":
          { "latitude": -35.283448299999996, "longitude": 149.128647 },
        "placeId": "ChIJWSb8ImpNFmsRp_4JAxJFE1A",
      },
      {
        "location": { "latitude": -35.2835199, "longitude": 149.1286054 },
        "placeId": "ChIJWSb8ImpNFmsRp_4JAxJFE1A",
      },
      {
        "location": { "latitude": -35.2835934, "longitude": 149.1285699 },
        "placeId": "ChIJWSb8ImpNFmsRp_4JAxJFE1A",
      },
      {
        "location":
          { "latitude": -35.283668899999995, "longitude": 149.12854059999998 },
        "placeId": "ChIJWSb8ImpNFmsRp_4JAxJFE1A",
      },
      {
        "location":
          { "latitude": -35.28372649999999, "longitude": 149.1285237 },
        "placeId": "ChIJWSb8ImpNFmsRp_4JAxJFE1A",
      },
      {
        "location":
          { "latitude": -35.28386179999999, "longitude": 149.12849319999998 },
        "placeId": "ChIJWSb8ImpNFmsRp_4JAxJFE1A",
      },
      {
        "location": { "latitude": -35.2839978, "longitude": 149.1284682 },
        "placeId": "ChIJWSb8ImpNFmsRp_4JAxJFE1A",
      },
      {
        "location":
          { "latitude": -35.2840205, "longitude": 149.12846779999998 },
        "placeId": "ChIJWSb8ImpNFmsRp_4JAxJFE1A",
      },
      {
        "location":
          { "latitude": -35.2840205, "longitude": 149.12846779999998 },
        "placeId": "ChIJZe8tFWpNFmsR4brZ1vldk2E",
      },
      {
        "location":
          { "latitude": -35.2840524, "longitude": 149.12845969999998 },
        "placeId": "ChIJZe8tFWpNFmsR4brZ1vldk2E",
      },
      {
        "location":
          { "latitude": -35.284341500000004, "longitude": 149.1284124 },
        "placeId": "ChIJZe8tFWpNFmsR4brZ1vldk2E",
      },
      {
        "location": { "latitude": -35.2843875, "longitude": 149.1284034 },
        "placeId": "ChIJZe8tFWpNFmsR4brZ1vldk2E",
      },
      {
        "location": { "latitude": -35.2843875, "longitude": 149.1284034 },
        "placeId": "ChIJVx7Ta2pNFmsRx9OI9CnN5tI",
      },
      {
        "location": { "latitude": -35.2845916, "longitude": 149.1283726 },
        "placeId": "ChIJVx7Ta2pNFmsRx9OI9CnN5tI",
      },
      {
        "location": { "latitude": -35.2845916, "longitude": 149.1283726 },
        "placeId": "ChIJtWxAZmpNFmsRlbUCkc6VtnA",
      },
      {
        "location":
          { "latitude": -35.28459730000001, "longitude": 149.1283703 },
        "placeId": "ChIJtWxAZmpNFmsRlbUCkc6VtnA",
      },
      {
        "location":
          { "latitude": -35.284728747199374, "longitude": 149.12834860726772 },
        "originalIndex": 7,
        "placeId": "ChIJtWxAZmpNFmsRlbUCkc6VtnA",
      },
    ],
}

يستخدم الردّ المخطّط التالي.

SnapToRoadsResponse

FieldRequiredTypeDescription
optional Array<SnappedPoint>

An array of snapped points.

See SnappedPoint for more information.

optionalstring

A string containing a user-visible warning.

SnappedPoint

FieldRequiredTypeDescription
requiredLatitudeLongitudeLiteral See LatitudeLongitudeLiteral for more information.
requiredstring

A unique identifier for a place. All place IDs returned by the Roads API correspond to road segments.

optionalnumber

An integer that indicates the corresponding value in the original request. Each value in the request should map to a snapped value in the response. However, if you've set interpolate=true or if you're using nearest roads, then it's possible that the response will contain more coordinates than the request. Interpolated values will not have an originalIndex. These values are indexed from 0, so a point with an originalIndex of 4 will be the snapped value of the 5th latitude/longitude passed to the path parameter. Nearest Roads points may contain several points for single coordinates with differing location or placeId.

LatitudeLongitudeLiteral

An object describing a specific location with Latitude and Longitude in decimal degrees.

FieldRequiredTypeDescription
requirednumber

Latitude in decimal degrees

requirednumber

Longitude in decimal degrees

عرض توضيحي

  1. انقر في جميع أنحاء الخريطة لإنشاء مسار مركبة. لاحظ أنه إذا النقاط متباعدة جدًا، لذا قد لا تلتقطها بشكل صحيح.
  2. انقر نقرًا مزدوجًا لمحاذاة المسار إلى الطريق.

يمكنك الاطّلاع على هذا المثال في وضع ملء الشاشة.

JavaScript

var apiKey = 'YOUR_API_KEY_HERE';

var map;
var drawingManager;
var placeIdArray = [];
var polylines = [];
var snappedCoordinates = [];

function initialize() {
  var mapOptions = {
    zoom: 17,
    center: {lat: -33.8667, lng: 151.1955,}
  };
  map = new google.maps.Map(document.getElementById('map'), mapOptions);

  // Adds a Places search box. Searching for a place will center the map on that
  // location.
  map.controls[google.maps.ControlPosition.RIGHT_TOP].push(
      document.getElementById('bar'));
  var autocomplete = new google.maps.places.Autocomplete(
      document.getElementById('autoc'));
  autocomplete.bindTo('bounds', map);
  autocomplete.addListener('place_changed', function() {
    var place = autocomplete.getPlace();
    if (place.geometry.viewport) {
      map.fitBounds(place.geometry.viewport);
    } else {
      map.setCenter(place.geometry.location);
      map.setZoom(17);
    }
  });

  // Enables the polyline drawing control. Click on the map to start drawing a
  // polyline. Each click will add a new vertice. Double-click to stop drawing.
  drawingManager = new google.maps.drawing.DrawingManager({
    drawingMode: google.maps.drawing.OverlayType.POLYLINE,
    drawingControl: true,
    drawingControlOptions: {
      position: google.maps.ControlPosition.TOP_CENTER,
      drawingModes: [
        google.maps.drawing.OverlayType.POLYLINE
      ]
    },
    polylineOptions: {
      strokeColor: '#696969',
      strokeWeight: 2,
      strokeOpacity: 0.3,
    }
  });
  drawingManager.setMap(map);

  // Snap-to-road when the polyline is completed.
  drawingManager.addListener('polylinecomplete', function(poly) {
    var path = poly.getPath();
    polylines.push(poly);
    placeIdArray = [];
    runSnapToRoad(path);
  });


  // Clear button. Click to remove all polylines.
  document.getElementById('clear').addEventListener('click', function(event) {
    event.preventDefault();
    for (var i = 0; i < polylines.length; ++i) {
      polylines[i].setMap(null);
    }
    polylines = [];
    return false;
  });
}

// Snap a user-created polyline to roads and draw the snapped path
function runSnapToRoad(path) {
  var pathValues = [];
  for (var i = 0; i < path.getLength(); i++) {
    pathValues.push(path.getAt(i).toUrlValue());
  }

  $.get('https://roads.googleapis.com/v1/snapToRoads', {
    interpolate: true,
    key: apiKey,
    path: pathValues.join('|')
  }, function(data) {
    processSnapToRoadResponse(data);
    drawSnappedPolyline();
  });
}

// Store snapped polyline returned by the snap-to-road service.
function processSnapToRoadResponse(data) {
  snappedCoordinates = [];
  placeIdArray = [];
  for (var i = 0; i < data.snappedPoints.length; i++) {
    var latlng = new google.maps.LatLng(
        data.snappedPoints[i].location.latitude,
        data.snappedPoints[i].location.longitude);
    snappedCoordinates.push(latlng);
    placeIdArray.push(data.snappedPoints[i].placeId);
  }
}

// Draws the snapped polyline (after processing snap-to-road response).
function drawSnappedPolyline() {
  var snappedPolyline = new google.maps.Polyline({
    path: snappedCoordinates,
    strokeColor: '#add8e6',
    strokeWeight: 4,
    strokeOpacity: 0.9,
  });

  snappedPolyline.setMap(map);
  polylines.push(snappedPolyline);
}

$(window).load(initialize);

JavaScript + HTML

<!DOCTYPE html>
<html>
  <head>
    <meta name="viewport" content="initial-scale=1.0, user-scalable=no">
    <meta charset="utf-8">
    <title>Roads API Demo</title>
    <style>
      html, body, #map {
        height: 100%;
        margin: 0px;
        padding: 0px
      }

      #panel {
        position: absolute;
        top: 5px;
        left: 50%;
        margin-left: -180px;
        z-index: 5;
        background-color: #fff;
        padding: 5px;
        border: 1px solid #999;
      }

      #bar {
        width: 240px;
        background-color: rgba(255, 255, 255, 0.75);
        margin: 8px;
        padding: 4px;
        border-radius: 4px;
      }

      #autoc {
        width: 100%;
        box-sizing: border-box;
      }
    </style>

    <script src="https://www.gstatic.com/external_hosted/jquery2.min.js"></script>
    <script
      src="https://maps.googleapis.com/maps/api/js?libraries=drawing,places&key=YOUR_API_KEY"></script>
    <script>
var apiKey = 'YOUR_API_KEY_HERE';

var map;
var drawingManager;
var placeIdArray = [];
var polylines = [];
var snappedCoordinates = [];

function initialize() {
  var mapOptions = {
    zoom: 17,
    center: {lat: -33.8667, lng: 151.1955,}
  };
  map = new google.maps.Map(document.getElementById('map'), mapOptions);

  // Adds a Places search box. Searching for a place will center the map on that
  // location.
  map.controls[google.maps.ControlPosition.RIGHT_TOP].push(
      document.getElementById('bar'));
  var autocomplete = new google.maps.places.Autocomplete(
      document.getElementById('autoc'));
  autocomplete.bindTo('bounds', map);
  autocomplete.addListener('place_changed', function() {
    var place = autocomplete.getPlace();
    if (place.geometry.viewport) {
      map.fitBounds(place.geometry.viewport);
    } else {
      map.setCenter(place.geometry.location);
      map.setZoom(17);
    }
  });

  // Enables the polyline drawing control. Click on the map to start drawing a
  // polyline. Each click will add a new vertice. Double-click to stop drawing.
  drawingManager = new google.maps.drawing.DrawingManager({
    drawingMode: google.maps.drawing.OverlayType.POLYLINE,
    drawingControl: true,
    drawingControlOptions: {
      position: google.maps.ControlPosition.TOP_CENTER,
      drawingModes: [
        google.maps.drawing.OverlayType.POLYLINE
      ]
    },
    polylineOptions: {
      strokeColor: '#696969',
      strokeWeight: 2,
      strokeOpacity: 0.3,
    }
  });
  drawingManager.setMap(map);

  // Snap-to-road when the polyline is completed.
  drawingManager.addListener('polylinecomplete', function(poly) {
    var path = poly.getPath();
    polylines.push(poly);
    placeIdArray = [];
    runSnapToRoad(path);
  });


  // Clear button. Click to remove all polylines.
  document.getElementById('clear').addEventListener('click', function(event) {
    event.preventDefault();
    for (var i = 0; i < polylines.length; ++i) {
      polylines[i].setMap(null);
    }
    polylines = [];
    return false;
  });
}

// Snap a user-created polyline to roads and draw the snapped path
function runSnapToRoad(path) {
  var pathValues = [];
  for (var i = 0; i < path.getLength(); i++) {
    pathValues.push(path.getAt(i).toUrlValue());
  }

  $.get('https://roads.googleapis.com/v1/snapToRoads', {
    interpolate: true,
    key: apiKey,
    path: pathValues.join('|')
  }, function(data) {
    processSnapToRoadResponse(data);
    drawSnappedPolyline();
  });
}

// Store snapped polyline returned by the snap-to-road service.
function processSnapToRoadResponse(data) {
  snappedCoordinates = [];
  placeIdArray = [];
  for (var i = 0; i < data.snappedPoints.length; i++) {
    var latlng = new google.maps.LatLng(
        data.snappedPoints[i].location.latitude,
        data.snappedPoints[i].location.longitude);
    snappedCoordinates.push(latlng);
    placeIdArray.push(data.snappedPoints[i].placeId);
  }
}

// Draws the snapped polyline (after processing snap-to-road response).
function drawSnappedPolyline() {
  var snappedPolyline = new google.maps.Polyline({
    path: snappedCoordinates,
    strokeColor: '#add8e6',
    strokeWeight: 4,
    strokeOpacity: 0.9,
  });

  snappedPolyline.setMap(map);
  polylines.push(snappedPolyline);
}

$(window).load(initialize);
    </script>
  </head>

  <body>
    <div id="map"></div>
    <div id="bar">
      <p class="auto"><input type="text" id="autoc"/></p>
      <p><a id="clear" href="#">Click here</a> to clear map.</p>
    </div>
  </body>
</html>