Snap to Roads

Le Roads API accepte jusqu'à 100 points GPS collectés sur un itinéraire et renvoie un ensemble de données similaire, avec les points alignés sur les routes les plus probables empruntées par le véhicule. Vous pouvez également demander que les points soient interpolés, ce qui génère un chemin qui suit en douceur la géométrie de la route.

Requêtes

Vous devez envoyer des requêtes d'alignement sur la route à l'aide du protocole HTTPS au format suivant :

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

Paramètres obligatoires

  • chemin d'accès

    Chemin à aligner. Le paramètre path accepte une liste de latitude/longitude pairs. Les valeurs de latitude et de longitude doivent être séparées par des virgules. Les coordonnées doivent être séparées par une barre verticale ("|"). Exemple : path=60.170880,24.942795|60.170879,24.942796|60.170877,24.942796.

    Remarque : L'algorithme d'alignement fonctionne mieux pour les points qui ne sont pas trop éloignés les uns des autres. Si vous constatez un comportement d'alignement étrange, essayez de créer des chemins dont les points sont plus proches les uns des autres. Pour garantir la meilleure qualité d'alignement sur la route, vous devez fournir des chemins sur lesquels les paires de points consécutives sont distantes de moins de 300 mètres. Cela vous aidera également à gérer les sauts longs et isolés, entre des points consécutifs causés par une perte de signal GPS ou du bruit.

Paramètres facultatifs

  • interpoler

    Indique si un chemin doit être interpolé pour inclure tous les points formant la géométrie complète de la route. Si la valeur est "true", des points interpolés supplémentaires sont également renvoyés, ce qui génère un chemin qui suit en douceur la géométrie de la route, même dans les virages et les tunnels. Les chemins interpolés contiennent probablement plus de points que le chemin d'origine. La valeur par défaut est false.

Exemples

La requête suivante aligne les points spécifiés sur la géométrie de la route. Cet ensemble de données particulier suit une route circulaire. Si vous définissez interpolate=true, la géométrie renvoyée correspond à la courbure de la route. Avec interpolate=false, le chemin aligné suit toujours la route, mais la polyligne résultante n'est pas aussi lisse.

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'

Réponses

Pour chaque requête valide, le Roads API renvoie une réponse au format indiqué dans l'URL de la requête, comme la réponse JSON suivante.

{
  "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",
      },
    ],
}

La réponse utilise le schéma suivant.

SnapToRoadsResponse

Champ Obligatoire Type Description
facultatif Array<SnappedPoint>

Tableau de points alignés.

Pour en savoir plus, consultez la section SnappedPoint.

facultatif chaîne

Chaîne contenant un avertissement visible par l'utilisateur.

SnappedPoint

Champ Obligatoire Type Description
obligatoire LatitudeLongitudeLiteral Pour en savoir plus, consultez la section LatitudeLongitudeLiteral.
obligatoire chaîne

Identifiant unique d'un lieu. Tous les ID de lieu renvoyés par l'API Roads correspondent à des segments de route.

facultatif nombre

Entier indiquant la valeur correspondante dans la requête d'origine. Chaque valeur de la requête doit correspondre à une valeur alignée dans la réponse. Toutefois, si vous avez défini interpolate=true ou si vous utilisez les routes les plus proches, il est possible que la réponse contienne plus de coordonnées que la requête. Les valeurs interpolées n'auront pas d'originalIndex. Ces valeurs sont indexées à partir de 0. Par conséquent, un point avec un originalIndex de 4 correspond à la valeur alignée de la 5e latitude/longitude transmise au paramètre path. Les points des routes les plus proches peuvent contenir plusieurs points pour des coordonnées uniques avec un lieu ou un placeId différents.

LatitudeLongitudeLiteral

Objet décrivant un lieu spécifique avec la latitude et la longitude en degrés décimaux.

Champ Obligatoire Type Description
obligatoire nombre

Latitude en degrés décimaux
obligatoire nombre

Longitude en degrés décimaux

Démo

  1. Cliquez sur la carte pour créer un trajet de véhicule. Notez que si vos points sont trop éloignés les uns des autres, ils risquent de ne pas s'aligner correctement.
  2. Double-cliquez pour aligner votre trajet sur la route.

Afficher cet exemple en plein écran.

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>