Driving distance area

Question

Is there a way, via the Google Maps API, to determine the bounding polygon within a given driving time of a given central point?

Failing that, is there a way to cal

Answer 1

• Marcelo's original driving radius demo original link is now dead.

• Marcelo's driving radius demo ported to v3

Note: these examples no longer work due to Google's policy change (You have exceeded your request quota for this API. error), replace the API key with an active one and they will work)

code snippet:

var map;
var container;
var zoom = 9;
var centerPoint = new google.maps.LatLng(35.149534, -90.04898);
var dirService = new google.maps.DirectionsService();
var centerMarker;
var circleMarkers = Array();
var circlePoints = Array();
var drivePolyPoints = Array();
var searchPolygon, drivePolygon;
var distToDrive = 30; // miles
var pointInterval = 30;
var searchPoints = [];
var polyline;
var polylines = [];
var redIcon8 = "https://maps.gstatic.com/intl/en_us/mapfiles/markers2/measle.png";

function initialize() {
  map = new google.maps.Map(
    document.getElementById("map_canvas"), {
      center: centerPoint,
      zoom: 9,
      mapTypeId: google.maps.MapTypeId.ROADMAP
    });
  google.maps.event.addListener(map, "click", mapClick);
}
google.maps.event.addDomListener(window, "load", initialize);

function mapClick(evt) {
  // map.clearOverlays();
  circleMarkers = Array();
  if (!centerMarker) {
    centerMarker = new google.maps.Marker({
      position: evt.latLng,
      map: map
    });
  } else {
    centerMarker.setMap(null);
    centerMarker.setPosition(evt.latLng);
  }
  centerMarker.setMap(map);
  searchPoints = getCirclePoints(evt.latLng, distToDrive);
  drivePolyPoints = Array();
  getDirections();
}

function getCirclePoints(center, radius) {
  var bounds = new google.maps.LatLngBounds();
  var circlePoints = Array();
  var searchPoints = Array();
  with(Math) {
    var rLat = (radius / 3963.189) * (180 / PI); // miles
    var rLng = rLat / cos(center.lat() * (PI / 180));
    for (var a = 0; a < 361; a++) {
      var aRad = a * (PI / 180);
      var x = center.lng() + (rLng * cos(aRad));
      var y = center.lat() + (rLat * sin(aRad));
      var point = new google.maps.LatLng(parseFloat(y), parseFloat(x), true);
      bounds.extend(point);
      circlePoints.push(point);
      if (a % pointInterval == 0) {
        searchPoints.push(point);
      }
    }
  }
  searchPolygon = new google.maps.Polygon({
    paths: circlePoints,
    strokeColor: '#0000ff',
    strokeWeight: 1,
    strokeOpacity: 1,
    fillColor: '#0000ff',
    fillOpacity: 0.2
  });
  searchPolygon.setMap(map);
  map.fitBounds(bounds);
  return searchPoints;
}

function getDirections() {
  if (!searchPoints.length) {
    return;
  }
  var to = searchPoints.shift();
  var request = {
    origin: centerMarker.getPosition(),
    destination: to,
    travelMode: google.maps.TravelMode.DRIVING
  };
  dirService.route(request, function(result, status) {
    if (status == google.maps.DirectionsStatus.OK) {
      var distance = parseInt(result.routes[0].legs[0].distance.value / 1609);
      var duration = parseFloat(result.routes[0].legs[0].duration.value / 3600).toFixed(2);
      var path = result.routes[0].overview_path;
      var legs = result.routes[0].legs;
      if (polyline && polyline.setPath) {
        polyline.setPath([]);
      } else {
        polyline = new google.maps.Polyline({
          path: [],
          // map: map,
          strokeColor: "#FF0000",
          strokeOpacity: 1
        });
      }
      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]);
            // bounds.extend(nextSegment[k]);
          }
        }
      }
      // polyline.setMap(map);
      shortenAndShow(polyline);
      getDirections();
    } else {
      console.log("Directions request failed, status=" + status + " [from:" + request.origin + " to:" + request.destination + "]");
      getDirections();
    }
  });
}

function shortenAndShow(polyline) {
  var distToDriveM = distToDrive * 1609;
  var dist = 0;
  var cutoffIndex = 0;
  var copyPoints = Array();
  for (var n = 0; n < polyline.getPath().getLength() - 1; n++) {
    dist += google.maps.geometry.spherical.computeDistanceBetween(polyline.getPath().getAt(n), polyline.getPath().getAt(n + 1));
    //GLog.write(dist + ' - ' + distToDriveM);
    if (dist < distToDriveM) {
      copyPoints.push(polyline.getPath().getAt(n));
    } else {
      break;
    }
  }
  var lastPoint = copyPoints[copyPoints.length - 1];
  var newLine = new google.maps.Polyline({
    path: copyPoints,
    strokeColor: '#ff0000',
    strokeWeight: 2,
    strokeOpacity: 1
  });
  newLine.setMap(map);
  polylines.push(newLine);
  drivePolyPoints.push(lastPoint);
  addBorderMarker(lastPoint, dist)
  if (drivePolyPoints.length > 3) {
    if (drivePolygon) {
      drivePolygon.setMap(null);
    }
    drivePolygon = new google.maps.Polygon({
      paths: drivePolyPoints,
      strokeColor: '#00ff00',
      strokeWeight: 1,
      strokeOpacity: 1,
      fillColor: '#00ff00',
      fillOpacity: 0.4
    });
    drivePolygon.setMap(map);
  }
}

function addBorderMarker(pt, d) {
  var str = pt.lat().toFixed(6) + ',' + pt.lng().toFixed(6) + ' - Driving Distance: ' + (d / 1609).toFixed(2) + ' miles';
  var marker = new google.maps.Marker({
    position: pt,
    icon: redIcon8,
    title: str
  });
  circleMarkers.push(marker);
  marker.setMap(map);
}

function clearOverlays() {
  for (var i = 0; i < circleMarkers.length; i++) {
    circleMarkers[i].setMap(null);
  }
  circleMarkers = [];
  for (var i = 0; i < circlePoints.length; i++) {
    circlePoints[i].setMap(null);
  }
  circlePoints = [];
  for (var i = 0; i < polylines.length; i++) {
    polylines[i].setMap(null);
  }
  polylines = [];
  if (searchPolygon && searchPolygon.setMap) searchPolygon.setMap(null);
  if (drivePolygon && drivePolygon.setMap) drivePolygon.setMap(null);
  if (centerMarker && centerMarker.setMap) centerMarker.setMap(null);
}

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

Clear | 
interval 30 (default) | 
interval 20 |