我正在开发一个谷歌地图项目，我正在填充谷歌地图，标记是从数据库中读取的（drawMarkers函数）。除此之外，谷歌地图会找到您当前的位置并每隔几秒钟保持刷新，以便在地图上跟踪您。我的问题是，最近的var也是我正在使用的函数，也找到最近的标记，然后从那里创建到当前位置的方向。我不知道如何实际找到最接近的标记，所以我从堆栈溢出中借用了另一个问题的代码，并试图使其适应这个项目。我需要帮助才能找到最近的标记，然后将其作为服务方向的目的地
$ionicSideMenuDelegate.canDragContent(false);
$scope.getTourMarkers = function () {
tourmarkers.getTourMarkers().success(function (data) {
$scope.tourmarkers = data;
console.log($scope.tourmarkers);
drawMarkers();
});
};
var drawMarkers = function () {
var markers;
var content;
var infoWindow;
for (var i = 0; i < $scope.tourmarkers.length; i++) {
content = '<h2>' + $scope.tourmarkers[i].title + '</h2>' +
'<br />' +
'<p>' +
'</p>';
infoWindow = new google.maps.InfoWindow({
content: content
});
var point = new google.maps.LatLng($scope.tourmarkers[i].lat, $scope.tourmarkers[i].lon);
markers = new google.maps.Marker({
label: "S",
animation: google.maps.Animation.DROP,
position: point,
map: map,
info: content
});
//SCOPE: 'this' refers to the current 'markers' object, we pass in the info and marker
google.maps.event.addListener(markers, 'click', function () {
infoWindow.setContent(this.info);
infoWindow.open(map, this);
});
}
};
var myLatlng = new google.maps.LatLng(38.5602, -121.4241);
var NAPA_HALL_LAT_LNG = new google.maps.LatLng(38.553801, -121.4212745); // just created this marker for testing purposes
var mapOptions = {
center: myLatlng,
zoom: 18,
mapTypeId: google.maps.MapTypeId.ROADMAP,
zoomControl: true,
disableDefaultUI: true
};
var map = new google.maps.Map(document.getElementById("map"), mapOptions);
var marker = new google.maps.Marker({
position: myLatlng,
map: map,
title: 'SAC STATE'
});
var dest = new google.maps.Marker({
position: NAPA_HALL_LAT_LNG,
map: map,
title: 'NAPA HALL'
});
///////////////////Directions Display//////////////////////
var directionsDisplay = new google.maps.DirectionsRenderer;
var directionsService = new google.maps.DirectionsService;
//////////////////////////////////////////////////////////////////////////////////////////
//Goal of this function is to find closest marker to current location
//then to create directions to that marker.
//should be refreshed everytime in the onSuccess function
var closest = function (directionsService, directionsDisplay, marker, dest) {
var event;
function rad(x) {return x*Math.PI/180;}
function find_closest_marker( event ) {
var lat = event.latLng.lat();
var lng = event.latLng.lng();
var R = 6371; // radius of earth in km
var distances = [];
var shortest = -1;
for( i=0;i < $scope.tourmarkers.length; i++) {
content = '<h2>' + $scope.tourmarkers[i].title + '</h2>' +
'<br />' +
'<p>' +
'</p>';
infoWindow = new google.maps.InfoWindow({
var mlat = $scope.tourmarkers[i].position.lat();
var mlng = $scope.tourmarkers[i].position.lng();
var dLat = rad(mlat - lat);
var dLong = rad(mlng - lng);
var a = Math.sin(dLat/2) * Math.sin(dLat/2) + Math.cos(rad(lat)) * Math.cos(rad(lat)) * Math.sin(dLong/2) * Math.sin(dLong/2);
var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
var d = R * c;
distances[i] = d;
if ( shortest == -1 || d < distances[shortest] ) {
shortest = i;
}
}
alert(map.markers[shortest].title);
}
/////**directions feature should have the closest marker be the desitination//
directionsService.route({
origin: marker.position,
destination: dest.position, // i think the marker that should in here is shortest.
travelMode: google.maps.TravelMode.WALKING
}, function(response,status) {
if(status==google.maps.DirectionsStatus.OK) {
directionsDisplay.setDirections(response);
} else {
window.alert('Directions request failed due to ' + status);
}
});
};
//////////////////////////////////////////////////////////////////////////////////////////
var onSuccess = function (position) {
marker.setPosition(new google.maps.LatLng(position.coords.latitude, position.coords.longitude));
directionsDisplay.setMap(map);
dest.setPosition(new google.maps.LatLng(38.553801, -121.4212745));
//dest.setPosition((closest(marker, $scope.tourmarkers)).position); // if you can get this line to work without commenting it out then you're set
closest(directionsService,directionsDisplay, marker,dest);
$scope.map = map;
//$scope.map.panTo(new google.maps.LatLng(position.coords.latitude, position.coords.longitude));
};
function onError(error) {
alert('code: ' + error.code + '\n' +
'message: ' + error.message + '\n');
}
navigator.geolocation.watchPosition(onSuccess, onError, {
maximumAge: 3000,
timeout: 5000,
enableHighAccuracy: true
});
除了最接近的功能外，该项目中的所有内容都正常工作。但即便如此，我已经测试了方向服务，甚至那也是有效的。我只需要帮助使方向服务中的目的地成为最接近当前位置的标记。
答案 0 :(得分：-1)
我认为此代码对您有帮助我在项目中使用此代码，以使您的要求与我的要求相同
在下面的函数'data'中表示来自服务器的lat lng列表
function initialize(data) {
size = 0;
counts = 0;
stops = data;
size = stops.length;
if (stops.length > 0) {
var map = new window.google.maps.Map(document
.getElementById("map"));
// new up complex objects before passing them around
var directionsDisplay = new window.google.maps.DirectionsRenderer(
{
suppressMarkers : true,
polylineOptions : {
strokeColor : "black"
}
});
var directionsService = new window.google.maps.DirectionsService();
Tour_startUp(stops);
window.tour.loadMap(map, directionsDisplay);
window.tour.fitBounds(map,stops);
/* if (stops.length > 1) */
window.tour.calcRoute(stops,directionsService,
directionsDisplay,size);
}
}
function Tour_startUp(stops) {
var stops=stops;
var counts=0;
if (!window.tour) window.tour = {
// map: google map object
// directionsDisplay: google directionsDisplay object (comes in empty)
loadMap: function (map, directionsDisplay) {
var myOptions = {
zoom:10,
center: new window.google.maps.LatLng(17.379818, 78.478542), // default to Hyderabad
mapTypeId: window.google.maps.MapTypeId.ROADMAP
};
map.setOptions(myOptions);
directionsDisplay.setMap(map);
},
fitBounds: function (map,stops) {
var bounds = new window.google.maps.LatLngBounds();
// extend bounds for each record
jQuery.each(stops, function (key, val) {
var myLatlng = new window.google.maps.LatLng(val.latitude, val.longitude);
bounds.extend(myLatlng);
});
map.fitBounds(bounds);
},
calcRoute: function (stops,directionsService, directionsDisplay,size) {
size=size;
var batches = [];
var itemsPerBatch = 10; // google API max = 10 - 1 start, 1 stop, and 8 waypoints
var itemsCounter = 0;
var wayptsExist = stops.length > 0;
var tempp=0;
while (wayptsExist) {
var subBatch = [];
var subitemsCounter = 0;
for (var j = itemsCounter; j < stops.length; j++) {
subitemsCounter++;
tempp++;
subBatch.push({
location: new window.google.maps.LatLng(stops[j].latitude, stops[j].longitude),
stopover: true
});
if (subitemsCounter == itemsPerBatch)
break;
}
itemsCounter += subitemsCounter;
batches.push(subBatch);
wayptsExist = itemsCounter < stops.length;
// If it runs again there are still points. Minus 1 before continuing to
// start up with end of previous tour leg
itemsCounter--;
}
// now we should have a 2 dimensional array with a list of a list of waypoints
var combinedResults;
var unsortedResults = [{}]; // to hold the counter and the results themselves as they come back, to later sort
var directionsResultsReturned = 0;
for (var k = 0; k < batches.length; k++) {
var lastIndex = batches[k].length - 1;
var start = batches[k][0].location;
//delay(600);
var end = batches[k][lastIndex].location;
// trim first and last entry from array
var waypts = [];
waypts = batches[k];
waypts.splice(0, 1);
waypts.splice(waypts.length - 1, 1);
var request = {
origin: start,
destination: end,
waypoints: waypts,
travelMode: window.google.maps.TravelMode.WALKING
};
(function (kk) {
directionsService.route(request, function (result, status) {
if (status == window.google.maps.DirectionsStatus.OK) {
var unsortedResult = { order: kk, result: result };
unsortedResults.push(unsortedResult);
//alert("count test");
directionsResultsReturned++;
if (directionsResultsReturned == batches.length) // we've received all the results. put to map
{
// sort the returned values into their correct order
unsortedResults.sort(function (a, b) { return parseFloat(a.order) - parseFloat(b.order); });
var count = 0;
for (var key in unsortedResults) {
if (unsortedResults[key].result != null) {
if (unsortedResults.hasOwnProperty(key)) {
if (count == 0) // first results. new up the combinedResults object
combinedResults = unsortedResults[key].result;
else {
// only building up legs, overview_path, and bounds in my consolidated object. This is not a complete
// directionResults object, but enough to draw a path on the map, which is all I need
combinedResults.routes[0].legs = combinedResults.routes[0].legs.concat(unsortedResults[key].result.routes[0].legs);
combinedResults.routes[0].overview_path = combinedResults.routes[0].overview_path.concat(unsortedResults[key].result.routes[0].overview_path);
combinedResults.routes[0].bounds = combinedResults.routes[0].bounds.extend(unsortedResults[key].result.routes[0].bounds.getNorthEast());
combinedResults.routes[0].bounds = combinedResults.routes[0].bounds.extend(unsortedResults[key].result.routes[0].bounds.getSouthWest());
}
count++;
}
}
}
directionsDisplay.setDirections(combinedResults);
var legs = combinedResults.routes[0].legs;
var summaryPanel = document.getElementById('directions_panel');
summaryPanel.innerHTML = '';
var totdist=0;
for (var i=0; i < legs.length;i++){
var markerletter = "A".charCodeAt(0);
var markerletter2= "B".charCodeAt(0)
markerletter += i;
markerletter2 += i;
markerletter = String.fromCharCode(markerletter);
markerletter2 = String.fromCharCode(markerletter2);
createMarker(directionsDisplay.getMap(),legs[i].start_location,legs[i].start_address,markerletter,size);//To display location address on the marker
var routeSegment = i + 1;
var point=+routeSegment+1;
summaryPanel.innerHTML += '<b>Route Segment: ' + routeSegment + '</b><br>';
summaryPanel.innerHTML += '<b>Point '+ routeSegment +' :</b>'+ ' ' +legs[i].start_address + ' <br> ';
summaryPanel.innerHTML += '<b>Point '+ point +' :</b>'+ ' '+legs[i].end_address + '<br>';
summaryPanel.innerHTML += '<b>Distance Covered '+' :</b>'+legs[i].distance.text + '<br><br>';
var test=legs[i].distance.text.split(' ');
var one=parseFloat(test[0]);
if(test[1]=="m"){
var one=parseFloat(test[0]/1000);
}
totdist=parseFloat(totdist)+parseFloat(one);
}
summaryPanel.innerHTML += '<b> Total Distance :'+totdist + 'km'+ '</b><br><br>';
var i=legs.length;
var markerletter = "A".charCodeAt(0);
markerletter += i;
markerletter = String.fromCharCode(markerletter);
createMarker(directionsDisplay.getMap(),legs[legs.length-1].end_location,legs[legs.length-1].end_address,markerletter,size);
}
}
});
})(k);
function delay(ms) {
ms += new Date().getTime();
while (new Date() < ms){}
}
}
}//calculate route end
};
}
//to show information on clicking marker
var infowindow = new google.maps.InfoWindow(
{
size: new google.maps.Size(150,50)
});
var icons = new Array();
icons["red"] = new google.maps.MarkerImage("mapIcons/marker_red.png",
// This marker is 20 pixels wide by 34 pixels tall.
new google.maps.Size(20, 34),
// The origin for this image is 0,0.
new google.maps.Point(0,0),
// The anchor for this image is at 9,34.
new google.maps.Point(9, 34));
function getMarkerImage(iconStr,size) {
counts++;
if(counts==size){
var markerimageLoc = "http://www.maps.google.com/mapfiles/ms/icons/blue.png";
counts = 0;
}else{
if (iconStr=="undefined") {
iconStr = "red";
var markerimageLoc = "http://www.maps.google.com/mapfiles/ms/icons/red.png";
}
else{
var markerimageLoc="http://www.google.com/mapfiles/marker"+ iconStr +".png";
// var markerimageLoc = "http://www.maps.google.com/mapfiles/ms/icons/red.png";
}
}
icons[iconStr] = new google.maps.MarkerImage(markerimageLoc,
// This marker is 20 pixels wide by 34 pixels tall.
new google.maps.Size(25, 34),
// The origin for this image is 0,0.
new google.maps.Point(0,0),
// The anchor for this image is at 6,20.
new google.maps.Point(9, 34));
return icons[iconStr];
}
// Marker sizes are expressed as a Size of X,Y
// where the origin of the image (0,0) is located
// in the top left of the image.
// Origins, anchor positions and coordinates of the marker
// increase in the X direction to the right and in
// the Y direction down.
var iconShadow = new google.maps.MarkerImage('http://www.google.com/mapfiles/shadow50.png',
// The shadow image is larger in the horizontal dimension
// while the position and offset are the same as for the main image.
new google.maps.Size(37, 34),
new google.maps.Point(0,0),
new google.maps.Point(9, 34));
// Shapes define the clickable region of the icon.
// The type defines an HTML <area> element 'poly' which
// traces out a polygon as a series of X,Y points. The final
// coordinate closes the poly by connecting to the first
// coordinate.
var iconShape = {
coord: [9,0,6,1,4,2,2,4,0,8,0,12,1,14,2,16,5,19,7,23,8,26,9,30,9,34,11,34,11,30,12,26,13,24,14,21,16,18,18,16,20,12,20,8,18,4,16,2,15,1,13,0],
type: 'poly'
};
function createMarker(map, latlng, label, character,size) {
var markerletter = character;
var size=size;
if (/[^a-zA-Z]/.test(character)) {
var markerletter = "undefined";
}
var contentString = '<b>' + label + '</b><br>';
var marker = new google.maps.Marker({
position : latlng,
map : map,
shadow : iconShadow,
icon : getMarkerImage(markerletter,size),
shape : iconShape,
title : label,
zIndex : Math.round(latlng.lat() * -100000) << 5
});
marker.myname = label;
google.maps.event.addListener(marker, 'click', function() {
infowindow.setContent(contentString);
infowindow.open(map, marker);
});
return marker;
}