javascript - How to set zoom level in google map

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javascript - How to set zoom level in google map

posted Oct 17, 2021 in Technique[技术] by 深蓝 (71.8m points)

javascript - How to set zoom level in google map

Here is the code I have written to add a marker to the google map by providing latitude and longitude. The problem is that I get a very highly zoomed google map. I have tried setting the zoom level to 1 but this has no effect to the very highly zoomed map.

 <script src="http://maps.google.com/maps/api/js?v=3&sensor=false" type="text/javascript"></script>
     <script type="text/javascript">
        var icon = new google.maps.MarkerImage("http://maps.google.com/mapfiles/ms/micons/blue.png",new google.maps.Size(32, 32), new google.maps.Point(0, 0),new google.maps.Point(16, 32));
        var center = null;
        var map = null;
        var currentPopup;
        var bounds = new google.maps.LatLngBounds();
        function addMarker(lat, lng, info) {
            var pt = new google.maps.LatLng(lat, lng);
            bounds.extend(pt);
            var marker = new google.maps.Marker({
                position: pt,
                icon: icon,
                map: map
            });
            var popup = new google.maps.InfoWindow({
                content: info,
                maxWidth: 300
            });
            google.maps.event.addListener(marker, "click", function() {
                if (currentPopup != null) {
                    currentPopup.close();
                    currentPopup = null;
                }
                popup.open(map, marker);
                currentPopup = popup;
            });
            google.maps.event.addListener(popup, "closeclick", function() {
                map.panTo(center);
                currentPopup = null;
            });
        }
        function initMap() {
            map = new google.maps.Map(document.getElementById("map"), {
            center: new google.maps.LatLng(0, 0),
            zoom: 1,
            mapTypeId: google.maps.MapTypeId.ROADMAP,
            mapTypeControl: false,
            mapTypeControlOptions: {
                style: google.maps.MapTypeControlStyle.HORIZONTAL_BAR
            },
            navigationControl: true,
            navigationControlOptions: {
                style: google.maps.NavigationControlStyle.SMALL
            }
        });
        addMarker(27.703402,85.311668,'New Road');
        center = bounds.getCenter();
        map.fitBounds(bounds);

        }
</script>
</head>
<body onload="initMap()" style="margin:0px; border:0px; padding:0px;">
<div id="map"></div>
</body>
</html>

How can i decrease the level of zoom for this case?

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1 Reply

深蓝 · Answer 1 · 2021-10-16T23:30:22+0000

Your code below is zooming the map to fit the specified bounds:

addMarker(27.703402,85.311668,'New Road');
center = bounds.getCenter();
map.fitBounds(bounds);

If you only have 1 marker and add it to the bounds, that results in the closest zoom possible:

function addMarker(lat, lng, info) {
  var pt = new google.maps.LatLng(lat, lng);
  bounds.extend(pt);
}

If you keep track of the number of markers you have "added" to the map (or extended the bounds with), you can only call fitBounds if that number is greater than one. I usually push the markers into an array (for later use) and test the length of that array.

If you will only ever have one marker, don't use fitBounds. Call setCenter, setZoom with the marker position and your desired zoom level.

function addMarker(lat, lng, info) {
  var pt = new google.maps.LatLng(lat, lng);
  map.setCenter(pt);
  map.setZoom(your desired zoom);
}

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

<html>

<head>
  <script src="http://maps.google.com/maps/api/js?key=AIzaSyCkUOdZ5y7hMm0yrcCQoCvLwzdM6M8s5qk" type="text/javascript"></script>
  <script type="text/javascript">
    var icon = new google.maps.MarkerImage("http://maps.google.com/mapfiles/ms/micons/blue.png", new google.maps.Size(32, 32), new google.maps.Point(0, 0), new google.maps.Point(16, 32));
    var center = null;
    var map = null;
    var currentPopup;
    var bounds = new google.maps.LatLngBounds();

    function addMarker(lat, lng, info) {
      var pt = new google.maps.LatLng(lat, lng);
      map.setCenter(pt);
      map.setZoom(5);
      var marker = new google.maps.Marker({
        position: pt,
        icon: icon,
        map: map
      });
      var popup = new google.maps.InfoWindow({
        content: info,
        maxWidth: 300
      });
      google.maps.event.addListener(marker, "click", function() {
        if (currentPopup != null) {
          currentPopup.close();
          currentPopup = null;
        }
        popup.open(map, marker);
        currentPopup = popup;
      });
      google.maps.event.addListener(popup, "closeclick", function() {
        map.panTo(center);
        currentPopup = null;
      });
    }

    function initMap() {
      map = new google.maps.Map(document.getElementById("map"), {
        center: new google.maps.LatLng(0, 0),
        zoom: 1,
        mapTypeId: google.maps.MapTypeId.ROADMAP,
        mapTypeControl: false,
        mapTypeControlOptions: {
          style: google.maps.MapTypeControlStyle.HORIZONTAL_BAR
        },
        navigationControl: true,
        navigationControlOptions: {
          style: google.maps.NavigationControlStyle.SMALL
        }
      });
      addMarker(27.703402, 85.311668, 'New Road');
      // center = bounds.getCenter();
      // map.fitBounds(bounds);

    }
  </script>
</head>

<body onload="initMap()" style="margin:0px; border:0px; padding:0px;">
  <div id="map"></div>
</body>

</html>

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javascript - How to set zoom level in google map

javascript - How to set zoom level in google map

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