CODEWITHSUNDEEP
javascriptgoogle-maps-api-3
ic90
ic90

Reputation: 444

Adding marker on Google Maps using a button

I'm trying to add a marker using a button in Google Maps and I'm getting the error, cannot read property lat of null. I'm not that good in Javascript, any help?

 function setmarker(){
        setLatLng = new google.maps.LatLng(document.getElementById('latitude').value,document.getElementById('longitude').value); 
        alert(setLatLng);
        var map = new google.maps.Map(document.getElementById('map-canvas'),
          mapOptions);

        var mapOptions = {
        zoom: 8,
        //center: new google.maps.LatLng(-1.2921897,36.8288574)
      };


        var marker = new google.maps.Marker({
          position: setLatLng,
          map: map,
          title: 'Obtained coordinate'
        });

    }
    </script>
  </head>
  <body>
<div id="map-canvas"></div>


<div class="side-panel">
  <div>Latitude:<br><input type="text" name="latitude" id="latitude" ></div>
  <div>Longitude:<br><input type="text" name="longitude" id="longitude"></div><br>
  <!-- <input type="submit" onsubmit="setmarker();"> -->
  <button onclick="setmarker()">Show Marker</button>
</div>

Upvotes: 0

Views: 1149

Answers (2)

ic90
ic90

Reputation: 444

Thanks for all the answers, stumbled upon the answer in the name of Reverse GeoCoding Service from Google that exactly did what I wanted to quite easily and in the exact way. From the API: https://developers.google.com/maps/documentation/javascript/examples/geocoding-reverse

var geocoder;
var map;
var infowindow = new google.maps.InfoWindow();
var marker;
function initialize() {
  geocoder = new google.maps.Geocoder();
  var latlng = new google.maps.LatLng(40.730885,-73.997383);
  var mapOptions = {
    zoom: 8,
    center: latlng,
    mapTypeId: 'roadmap'
  }
  map = new google.maps.Map(document.getElementById('map-canvas'), mapOptions);
}

function codeLatLng() {
  var input = document.getElementById('latlng').value;
  var latlngStr = input.split(',', 2);
  var lat = parseFloat(latlngStr[0]);
  var lng = parseFloat(latlngStr[1]);
  var latlng = new google.maps.LatLng(lat, lng);
  geocoder.geocode({'latLng': latlng}, function(results, status) {
    if (status == google.maps.GeocoderStatus.OK) {
      if (results[1]) {
        map.setZoom(11);
        marker = new google.maps.Marker({
            position: latlng,
            map: map
        });
        infowindow.setContent(results[1].formatted_address);
        infowindow.open(map, marker);
      } else {
        alert('No results found');
      }
    } else {
      alert('Geocoder failed due to: ' + status);
    }
  });
}

google.maps.event.addDomListener(window, 'load', initialize);

Upvotes: 0

duncan
duncan

Reputation: 31912

When you do document.getElementById('latitude').value that returns the value as a string e.g. "51.23546" instead of the floating point number that Google's API expects.

To make sure they get passed to Google as floats, try:

setLatLng = new google.maps.LatLng(
    parseFloat(document.getElementById('latitude').value),       
    parseFloat(document.getElementById('longitude').value)
);

Upvotes: 1

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