Google Maps API directionsService.route different from Google Maps Directions

问题

I'm using Google Maps JS API to search for nearby places, i.e. restaurants based on my LatLng :

var request = {
        location: myLocation,
        rankBy: google.maps.places.RankBy.DISTANCE,
        types: ['bar', 'cafe', 'food', 'liquor_store', 'lodging', 'meal_delivery', 'meal_takeaway', 'night_club', 'restaurant'],
        keyword: ['bar', 'pub']
    };
searchService.nearbySearch(request, callback);

I get the Results Array and want to show directions to the first place from the array :

var request = {
        origin: myLocation,
        destination: bars[0].geometry.location,
        travelMode: google.maps.TravelMode.WALKING
};
directionsService.route(request, function (response, status) {
        if (status == google.maps.DirectionsStatus.OK) {
            directionsDisplay.setDirections(response);
            directionsDisplay.setOptions({
                suppressMarkers: true
            });
            var myRoute = response.routes[0].legs[0];
            for (var i = 0; i < myRoute.steps.length; i++) {
                Map.marker(myRoute.steps[i].start_location, myRoute.steps[i].instructions);
            }
        } else {
            console.log("directionsService : " + status);
        }
    });

where bars[0] is the array with results from the searchService.nearbySearch query.

I do get the directions, however the last "dotted leg" seems to be missing even though the pin is placed correctly. When you compare it to the maps.google.com directions there's that dotted leg between the pin and direction route.

My API directions : http://damianbilski.com/temp/api_example.png

Maps.google.com directions : http://damianbilski.com/temp/online_example.png

Any idea how to get that last dotted leg with directionsService.route. Many thanks for all your help!

回答1:

The Google Maps Javascript API v3 directions service won't do that for you (at least at present). You can add a "dotted" polyline from the end of the directions result to the location of the place if you want to.

proof of concept fiddle

code snippet:

var geocoder;
var map;
var searchService;
var myLocation;
var directionsService = new google.maps.DirectionsService();
var directionsDisplay = new google.maps.DirectionsRenderer();

function initialize() {
  var map = new google.maps.Map(
    document.getElementById("map_canvas"), {
      center: new google.maps.LatLng(37.4419, -122.1419),
      zoom: 13,
      mapTypeId: google.maps.MapTypeId.ROADMAP
    });
  myLocation = map.getCenter();
  var marker = new google.maps.Marker({
    position: myLocation,
    map: map
  });
  searchService = new google.maps.places.PlacesService(map);
  directionsDisplay.setMap(map);
  var request = {
    location: myLocation,
    rankBy: google.maps.places.RankBy.DISTANCE,
    types: ['bar', 'cafe', 'food', 'liquor_store', 'lodging', 'meal_delivery', 'meal_takeaway', 'night_club', 'restaurant'],
    keyword: ['bar', 'pub']
  };
  searchService.nearbySearch(request, function(bars, status) {
    if (status === google.maps.places.PlacesServiceStatus.OK) {
      var barMark = new google.maps.Marker({
        position: bars[0].geometry.location,
        map: map,
        icon: {
          url: "https://maps.gstatic.com/intl/en_us/mapfiles/markers2/measle.png",
          size: new google.maps.Size(7, 7),
          anchor: new google.maps.Point(3.5, 3.5)
        }
      });
      var request = {
        origin: myLocation,
        destination: bars[0].geometry.location,
        travelMode: google.maps.TravelMode.WALKING
      };
      directionsService.route(request, function(response, status) {
        if (status == google.maps.DirectionsStatus.OK) {
          directionsDisplay.setDirections(response);
          directionsDisplay.setOptions({
            suppressMarkers: true,
            preserveViewport: true
          });
          var polyline = getPolyline(response);
          map.setCenter(polyline.getPath().getAt(polyline.getPath().getLength() - 1));
          map.setZoom(19);

          var lineLength = google.maps.geometry.spherical.computeDistanceBetween(bars[0].geometry.location, polyline.getPath().getAt(polyline.getPath().getLength() - 1));
          var lineHeading = google.maps.geometry.spherical.computeHeading(bars[0].geometry.location, polyline.getPath().getAt(polyline.getPath().getLength() - 1));
          var markerO = new google.maps.Marker({
            position: google.maps.geometry.spherical.computeOffset(bars[0].geometry.location, lineLength * 0.1, lineHeading)
          });
          var markerD = new google.maps.Marker({
            position: google.maps.geometry.spherical.computeOffset(bars[0].geometry.location, lineLength * 0.9, lineHeading)
          });

          var markerA = new google.maps.Marker({
            position: google.maps.geometry.spherical.computeOffset(markerO.getPosition(), lineLength / 3, lineHeading - 40)
          });
          var markerB = new google.maps.Marker({
            position: google.maps.geometry.spherical.computeOffset(markerD.getPosition(), lineLength / 3, lineHeading - 140)
          });

          var curvedLine = new GmapsCubicBezier(markerO.getPosition(), markerA.getPosition(), markerB.getPosition(), markerD.getPosition(), 0.01, map);

          var line = new google.maps.Polyline({
            path: [bars[0].geometry.location, polyline.getPath().getAt(polyline.getPath().getLength() - 1)],
            strokeOpacity: 0,
            icons: [{
              icon: {
                path: 'M 0,-1 0,1',
                strokeOpacity: 1,
                scale: 4
              },
              offset: '0',
              repeat: '20px'
            }],
            // map: map
          });
        } else {
          console.log("directionsService : " + status);
        }
      });
    }
  });
}
google.maps.event.addDomListener(window, "load", initialize);

function getPolyline(result) {
  var polyline = new google.maps.Polyline({
    path: []
  });
  var path = result.routes[0].overview_path;
  var legs = result.routes[0].legs;
  for (i = 0; i < legs.length; i++) {
    var steps = legs[i].steps;
    for (j = 0; j < steps.length; j++) {
      var nextSegment = steps[j].path;
      for (k = 0; k < nextSegment.length; k++) {
        polyline.getPath().push(nextSegment[k]);
      }
    }
  }
  return polyline;
}

var GmapsCubicBezier = function(latlong1, latlong2, latlong3, latlong4, resolution, map) {
  var lat1 = latlong1.lat();
  var long1 = latlong1.lng();
  var lat2 = latlong2.lat();
  var long2 = latlong2.lng();
  var lat3 = latlong3.lat();
  var long3 = latlong3.lng();
  var lat4 = latlong4.lat();
  var long4 = latlong4.lng();

  var points = [];

  for (it = 0; it <= 1; it += resolution) {
    points.push(this.getBezier({
      x: lat1,
      y: long1
    }, {
      x: lat2,
      y: long2
    }, {
      x: lat3,
      y: long3
    }, {
      x: lat4,
      y: long4
    }, it));
  }
  var path = [];
  for (var i = 0; i < points.length - 1; i++) {
    path.push(new google.maps.LatLng(points[i].x, points[i].y));
    path.push(new google.maps.LatLng(points[i + 1].x, points[i + 1].y, false));
  }

  var Line = new google.maps.Polyline({
    path: path,
    geodesic: true,
    strokeOpacity: 0.0,
    icons: [{
      icon: {
        path: 'M 0,-1 0,1',
        strokeOpacity: 1,
        scale: 4
      },
      offset: '0',
      repeat: '20px'
    }],
    strokeColor: 'grey'
  });

  Line.setMap(map);

  return Line;
};


GmapsCubicBezier.prototype = {

  B1: function(t) {
    return t * t * t;
  },
  B2: function(t) {
    return 3 * t * t * (1 - t);
  },
  B3: function(t) {
    return 3 * t * (1 - t) * (1 - t);
  },
  B4: function(t) {
    return (1 - t) * (1 - t) * (1 - t);
  },
  getBezier: function(C1, C2, C3, C4, percent) {
    var pos = {};
    pos.x = C1.x * this.B1(percent) + C2.x * this.B2(percent) + C3.x * this.B3(percent) + C4.x * this.B4(percent);
    pos.y = C1.y * this.B1(percent) + C2.y * this.B2(percent) + C3.y * this.B3(percent) + C4.y * this.B4(percent);
    return pos;
  }
};

html,
body,
#map_canvas {
  height: 100%;
  width: 100%;
  margin: 0px;
  padding: 0px
}

<script src="https://maps.googleapis.com/maps/api/js?libraries=places"></script>
<div id="map_canvas"></div>

回答2:

Thanks for your answer @geocodezip, in case someone else needs it :

https://developers.google.com/maps/documentation/javascript/examples/overlay-symbol-dashed

services.directions.set.route(request, function (response, status) {
        if (status == google.maps.DirectionsStatus.OK) {
            services.directions.display.setDirections(response);
            var myRoute = response.routes[0].legs[0];
            var lineSymbol = {
                path: 'M 0,-1 0,1',
                strokeOpacity: 1,
                scale: 4
            };
            var line = new google.maps.Polyline({
                path: [myRoute.steps[myRoute.steps.length - 1].end_point, to.geometry.location],
                strokeOpacity: 0,
                strokeColor: "#7d7d7d",
                icons: [{
                    icon: lineSymbol,
                    offset: '0',
                    repeat: '20px'
                }],
                map: map
            });
        }
    });

来源：https://stackoverflow.com/questions/32596050/google-maps-api-directionsservice-route-different-from-google-maps-directions

标签

javascript

google-maps

google-maps-api-3

directions