从谷歌标记获取 Lat/Lng

我用一个可拖动的标记做了一个谷歌地图。当用户拖动标记时,我需要知道新的经纬度,但我不知道怎样做才是最好的方法。

我如何检索新的坐标?

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You could just call ABC0 on the Marker - have you tried that?

If you're on the deprecated, v2 of the JavaScript API, you can call ABC0 on GMarker.

You should add a listener on the marker and listen for the drag or dragend event, and ask the event its position when you receive this event.

See http://code.google.com/intl/fr/apis/maps/documentation/javascript/reference.html#Marker for the description of events triggered by the marker. And see http://code.google.com/intl/fr/apis/maps/documentation/javascript/reference.html#MapsEventListener for methods allowing to add event listeners.

Here is the JSFiddle Demo. In Google Maps API V3 it's pretty simple to track the lat and lng of a draggable marker. Let's start with the following HTML and CSS as our base.

<div id='map_canvas'></div>
<div id="current">Nothing yet...</div>


#map_canvas{
width: 400px;
height: 300px;
}


#current{
padding-top: 25px;
}

Here is our initial JavaScript initializing the google map. We create a marker that we want to drag and set it's draggable property to true. Of course keep in mind it should be attached to an onload event of your window for it to be loaded, but i'll skip to the code:

var map = new google.maps.Map(document.getElementById('map_canvas'), {
zoom: 1,
center: new google.maps.LatLng(35.137879, -82.836914),
mapTypeId: google.maps.MapTypeId.ROADMAP
});


var myMarker = new google.maps.Marker({
position: new google.maps.LatLng(47.651968, 9.478485),
draggable: true
});

Here we attach two events dragstart to track the start of dragging and dragend to drack when the marker stop getting dragged, and the way we attach it is to use google.maps.event.addListener. What we are doing here is setting the div current's content when marker is getting dragged and then set the marker's lat and lng when drag stops. Google mouse event has a property name 'latlng' that returns 'google.maps.LatLng' object when the event triggers. So, what we are doing here is basically using the identifier for this listener that gets returned by the google.maps.event.addListener and get the property latLng to extract the dragend's current position. Once we get that Lat Lng when the drag stops we'll display within your current div:

google.maps.event.addListener(myMarker, 'dragend', function(evt){
document.getElementById('current').innerHTML = '<p>Marker dropped: Current Lat: ' + evt.latLng.lat().toFixed(3) + ' Current Lng: ' + evt.latLng.lng().toFixed(3) + '</p>';
});


google.maps.event.addListener(myMarker, 'dragstart', function(evt){
document.getElementById('current').innerHTML = '<p>Currently dragging marker...</p>';
});

Lastly, we'll center our marker and display it on the map:

map.setCenter(myMarker.position);
myMarker.setMap(map);

Let me know if you have any questions regarding my answer.

// show the marker position //


console.log( objMarker.position.lat() );
console.log( objMarker.position.lng() );


// create a new point based into marker position //


var deltaLat = 1.002;
var deltaLng = -1.003;


var objPoint = new google.maps.LatLng(
parseFloat( objMarker.position.lat() ) + deltaLat,
parseFloat( objMarker.position.lng() ) + deltaLng
);


// now center the map using the new point //


objMap.setCenter( objPoint );

try this

var latlng = new google.maps.LatLng(51.4975941, -0.0803232);
var map = new google.maps.Map(document.getElementById('map'), {
center: latlng,
zoom: 11,
mapTypeId: google.maps.MapTypeId.ROADMAP
});
var marker = new google.maps.Marker({
position: latlng,
map: map,
title: 'Set lat/lon values for this property',
draggable: true
});


google.maps.event.addListener(marker, 'dragend', function (event) {
document.getElementById("latbox").value = this.getPosition().lat();
document.getElementById("lngbox").value = this.getPosition().lng();
});

There are a lot of answers to this question, which never worked for me (including suggesting getPosition() which doesn't seem to be a method available for markers objects). The only method that worked for me in maps V3 is (simply) :

var lat = marker.lat();
var long = marker.lng();
var lat = marker.getPosition().lat();
var lng = marker.getPosition().lng();

More information can be found at Google Maps API - LatLng

var map = new google.maps.Map(document.getElementById('map_canvas'), {
zoom: 10,
center: new google.maps.LatLng(13.103, 80.274),
mapTypeId: google.maps.MapTypeId.ROADMAP
});


var myMarker = new google.maps.Marker({
position: new google.maps.LatLng(18.103, 80.274),
draggable: true
});


google.maps.event.addListener(myMarker, 'dragend', function(evt) {
document.getElementById('current').innerHTML = '<p>Marker dropped: Current Lat: ' + evt.latLng.lat().toFixed(3) + ' Current Lng: ' + evt.latLng.lng().toFixed(3) + '</p>';
});
google.maps.event.addListener(myMarker, 'dragstart', function(evt) {
document.getElementById('current').innerHTML = '<p>Currently dragging marker...</p>';
});
map.setCenter(myMarker.position);
myMarker.setMap(map);


function getLocation() {
if (navigator.geolocation) {
navigator.geolocation.getCurrentPosition(showPosition);
} else {
x.innerHTML = "Geolocation is not supported by this browser.";
}
}


function showPosition(position) {
document.getElementById('current').innerHTML = '<p>Marker dropped: Current Lat: ' + position.coords.latitude + ' Current Lng: ' + position.coords.longitude + '</p>';
var myMarker = new google.maps.Marker({
position: new google.maps.LatLng(position.coords.latitude, position.coords.longitude),
draggable: true
});
google.maps.event.addListener(myMarker, 'dragend', function(evt) {
document.getElementById('current').innerHTML = '<p>Marker dropped: Current Lat: ' + evt.latLng.lat().toFixed(3) + ' Current Lng: ' + evt.latLng.lng().toFixed(3) + '</p>';
});
google.maps.event.addListener(myMarker, 'dragstart', function(evt) {
document.getElementById('current').innerHTML = '<p>Currently dragging marker...</p>';
});
map.setCenter(myMarker.position);
myMarker.setMap(map);
}
getLocation();
#map_canvas {
width: 980px;
height: 500px;
}


#current {
padding-top: 25px;
}
<script src="http://maps.google.com/maps/api/js?sensor=false&.js"></script>
<!DOCTYPE html>
<html lang="en">


<head>


</head>


<body>
<section>
<div id='map_canvas'></div>
<div id="current">
<p>Marker dropped: Current Lat:18.103 Current Lng:80.274</p>
</div>
</section>




</body>


</html>