How do I get the latlng after the dragend event in leaflet?

Question

I'm trying to update the lat/lng value of a marker after it is moved. The example provided uses a popup window to display the lat/lng.

I have a "dragend" event listener for the marker, but when I alert the value of e.latlng it returns undefined.

javascript:

function markerDrag(e){
    alert("You dragged to: " + e.latlng);
}

function initialize() {
    // Initialize the map
    var map = L.map('map').setView([38.487, -75.641], 8);
    L.tileLayer('http://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png', {
        attribution: 'Map data &copy; <a href="http://openstreetmap.org">OpenStreetMap</a> contributors, <a href="http://creativecommons.org/licenses/by-sa/2.0/">CC-BY-SA</a>',
        maxZoom: 18
    }).addTo(map);

    // Event Handlers
    map.on('click', function(e){
        var marker = new L.Marker(e.latlng, {draggable:true});
        marker.bindPopup("<strong>"+e.latlng+"</strong>").addTo(map);

        marker.on('dragend', markerDrag);
    });
}


$(document).ready(initialize());

http://jsfiddle.net/rhewitt/Msrpq/4/

Ernaline

Answer 1

latlng value is not in e.latlng but in e.target._latlng . Use console.

Archduke

How did you use the console to find that it was actually e.target._latlng? – Ernaline

put a debugger in fiddle – Archduke

Give an example? I don't know how to console out a property I'm not aware of. – Ernaline

write "debugger"; where you want to break and open the console.(reload the page :) ) . Once the break point is hit, hover over the property or type in console. You can see all the contents. this will help.. developers.google.com/chrome-developer-tools/docs/… – Archduke

It's better to use e.target.getLatLng(); that way we're not exposing any private variables. – Ambo

Answer 2

Use e.target.getLatLng() to get the latlng of the updated position.

// Script for adding marker on map click
function onMapClick(e) {

    var marker = L.marker(e.latlng, {
             draggable:true,
             title:"Resource location",
             alt:"Resource Location",
             riseOnHover:true
            }).addTo(map)
              .bindPopup(e.latlng.toString()).openPopup();

    // #12 : Update marker popup content on changing it's position
    marker.on("dragend",function(e){

        var changedPos = e.target.getLatLng();
        this.bindPopup(changedPos.toString()).openPopup();

    });
}

JSFiddle demo

Clamor

The key piece of this that answers the OP's question is ev.target.getLatLng(). – Beaconsfield

Is there anyway for folium, I can't find this answer for folium. – Somatist

This is what I want, but on folium. – Somatist

Answer 3

While using e.target._latlng works (as proposed by this other answer), it's better practice to use

e.target.getLatLng();

That way we're not exposing any private variables, as is recommended by Leaflet:

Private properties and methods start with an underscore (_). This doesn’t make them private, just recommends developers not to use them directly.

Ambo

e.target.getLatLng is not a function – Kurgan

BTW, const { lat, lng } = e.target.getCenter(); is working perfectly for me – Kurgan

Answer 4

I think the API changed.

Nowadays is: const { lat, lng } = e.target.getCenter();

Kurgan

What object are you clicking on and what version of Leaflet? I only see the getCenter() method available for L.map, L.latLngBounds and L.polyline for Leaflet 1.0.3. On the other hand, getLatLng() is available for L.marker, L.popup, and L.circleMarker. – Ambo

The API has not changed. In 1.3.0, for markers, this is still e.target.getLatLng(). – Beaconsfield

This helped! On Leaflet version 1.0.3 here. No getLatLng method. I got as far to looking in the console and found various L.Point classes, but this was the data I wanted. Even in the source version of Leaflet, I only saw the target object as NewClass, which didn't help for looking through the docs online, and I also did not see much in the way of a "move" event that I was using. – Keener

Answer 5

if anyone is using react than you should use :

const map = useMap()
map.addEventListener("dragend" , ()=> {
const {lat , lng} = map.getCenter()
})

Ossieossietzky