Google Maps v3 fitBounds() Zoom too close for single marker

Is there a way to set a max zoom level for fitBounds()?

My problem is that when the map is only fed one location,开发者_如何学编程 it zooms in as far as it can go, which really takes the map out of context and renders it useless. Perhaps I am taking the wrong approach?

I like mrt's solution (especially when you don't know how many points you will be mapping or adjusting for), except it throws the marker off so that it isn't in the center of the map anymore. I simply extended it by an additional point subtracting .01 from the lat and lng as well, so it keeps the marker in the center. Works great, thanks mrt!

// Pan & Zoom map to show all markers
function fitToMarkers(markers) {

    var bounds = new google.maps.LatLngBounds();

    // Create bounds from markers
    for( var index in markers ) {
        var latlng = markers[index].getPosition();
        bounds.extend(latlng);
    }

    // Don't zoom in too far on only one marker
    if (bounds.getNorthEast().equals(bounds.getSouthWest())) {
       var extendPoint1 = new google.maps.LatLng(bounds.getNorthEast().lat() + 0.01, bounds.getNorthEast().lng() + 0.01);
       var extendPoint2 = new google.maps.LatLng(bounds.getNorthEast().lat() - 0.01, bounds.getNorthEast().lng() - 0.01);
       bounds.extend(extendPoint1);
       bounds.extend(extendPoint2);
    }

    map.fitBounds(bounds);

    // Adjusting zoom here doesn't work :/

}

You can setup your map with maxZoom in the MapOptions ^{(api-reference)} like this:

var map = new google.maps.Map(document.getElementById("map"), { maxZoom: 10 });

This would keep the map from zooming any deeper when using fitBounds() and even removes the zoom levels from the zoom control.

Another solution is to expand bounds if you detect they are too small before you execute fitBounds():

var bounds = new google.maps.LatLngBounds();
// here you extend your bound as you like
// ...
if (bounds.getNorthEast().equals(bounds.getSouthWest())) {
   var extendPoint = new google.maps.LatLng(bounds.getNorthEast().lat() + 0.01, bounds.getNorthEast().lng() + 0.01);
   bounds.extend(extendPoint);
}
map.fitBounds(bounds);

Once you've added all of the real bounds add these lines

var offset = 0.002;     
var center = bounds.getCenter();                            
bounds.extend(new google.maps.LatLng(center.lat() + offset, center.lng() + offset));
bounds.extend(new google.maps.LatLng(center.lat() - offset, center.lng() - offset));

it get the center of the real bounds then adds two additional points one to the northeast and one to the southwest of you center

This effectively sets the minimum zoom, change the value of offset to increase or decrease the zoom

var map = new google.maps.Map(document.getElementById("map"), { maxZoom: 10 });

Using the MaxZoom option works best for not zooming to close on to the marks you have.

If it is for a single location, you can use setCenter() and setZoom() instead.

u can use

map.setOptions({
    maxZoom: [what u want],
    minZoom: [what u want]
});

this way u set the properties of the map after the map has been initialized .... u can set them as many times as u want ... but in ur case ... u can set them before fitBounds()

good luck, rarutu

The way I prevent the map from zooming in to far is by adding this line of code:

var zoomOverride = map.getZoom();
        if(zoomOverride > 15) {
        zoomOverride = 15;
        }
      map.setZoom(zoomOverride);

Directly after this line:

map.setCenter(bounds.getCenter(), map.getBoundsZoomLevel(bounds));

Feel free to change the zoom level to whatever level you don’t want the map to zoom past.

If you have any problems or questions, just leave me a comment on the blog post I wrote about this at http://icode4you.net/creating-your-own-store-locator-map-how-to-prevent-the-map-from-zooming-in-too-close-on-a-single-marker

I really like mrt's solution and it works perfectly if you've always only have one point to work with. I did however find that if the bounding box was not based on one point, but the points were very close together, this could still cause the map to be zoomed in too far.

Here's a way to first check if the points are within a defined distance of each other, then if they are smaller than that minimum distance, extend the bounds by that minimum distance:

var bounds = new google.maps.LatLngBounds();
// here you extend your bound as you like

// ...

var minDistance = 0.002;
var sumA = bounds.getNorthEast().lng() - bounds.getSouthWest().lng();
var sumB = bounds.getNorthEast().lat() - bounds.getSouthWest().lat();

if((sumA < minDistance && sumA > -minDistance) 
&& (sumB < minDistance && sumB > -minDistance)){
var extendPoint1 = new google.maps.LatLng(bounds.getNorthEast().lat() + minDistance, bounds.getNorthEast().lng() + minDistance);
    var extendPoint2 = new google.maps.LatLng(bounds.getNorthEast().lat() - minDistance, bounds.getNorthEast().lng() - minDistance);
    bounds.extend(extendPoint1);
    bounds.extend(extendPoint2);
}

Hope this helps someone!

As for me guys i solve it by creating an idle event after fitBounds. Working perfectly. Guess that's one of the most clean solutions here

var locations = [['loc', lat, lng], ['loc', lat, lng]];
.....
for (i = 0; i < locations.length; i++) { 
  var map = new google.maps.Map(document.getElementById('map'), {
    zoom: 10
  });
  .... create markers, etc.
}
....
map.fitBounds(bounds);  
google.maps.event.addListenerOnce(map, 'idle', function() {
  if (locations.length == 1) {
    map.setZoom(11);
  }
});

This gives you a direct control upon max allowed zoom on bounds fitting.

var fitToMarkers = function(map, markers, maxZoom) {
    if (typeof maxZoom == 'undefined') maxZoom = 15;

    google.maps.event.addListenerOnce(map, 'bounds_changed', function(event) {
        if (this.getZoom() > maxZoom) {
            this.setZoom(maxZoom);
        }
    });

    var bounds = new google.maps.LatLngBounds();
    for (var m = 0; m < markers.length; m++) {
        var marker = markers[m];
        var latlng = marker.getPosition();
        bounds.extend(latlng);
    }

    map.fitBounds(bounds);
};

I solved with this chunk, since Google Maps V3 is event driven:

you can tell the API to set back the zoom to a proper amount when the zoom_changed event triggers:

var initial = true
google.maps.event.addListener(map, "zoom_changed", function() {
    if (intial == true){
       if (map.getZoom() > 11) {
         map.setZoom(11);
         intial = false;
       }
    }
}); 

I used intial make the map not zooming too much loading when the eventual fitBounds permorfed, without it any zoom event over 11 would be impossible for the user.

After calling fitBounds() method, try to setup zoom level again. It will force the map to be at that zoom level whilst being centered at the right place.

I have soulution based on limiting max zoom when fitting bounds. Works for me (tested on Win 7 - IE 9, FF 13, Chrome 19):

// When fitting bounds:
var bounds = new google.maps.LatLngBounds();
// ...
// extend bounds as you like
// ..

// now set global variable when fitting bounds
window.fittingBounds = true;
map.fitBounds(bounds);
window.fittingBounds = false;


// attach this event listener after map init
google.maps.event.addListener(map, 'zoom_changed', function() {
    // set max zoom only when fitting bounds
    if (window.fittingBounds && map.getZoom() > 16) {
        this.setZoom(16);
    }
});

And .. here is another one.
Same idea as mrt and Ryan, but

• also works if bounds size is not exactly zero (*)
• prevents distortion near the poles
• uses getCenter() instead of getNorthEast()

(*) Note: If the box is already big enough, then adding those two extra points should have no effect. So we don't need any further checking.

function calcBounds(markers) {
  // bounds that contain all markers
  var bounds = new google.maps.LatLngBounds();
  // Using an underscore _.each(). Feel free to replace with standard for()
  _.each(markers, function(marker) {
    bounds.extend(marker.getPosition());
  });
  // prevent lat/lng distortion at the poles
  var lng0 = bounds.getNorthEast().lng();
  var lng1 = bounds.getSouthWest().lng();
  if (lng0 * lng1 < 0) {
    // Take the cos at the equator.
    var cos = 1;
  }
  else {
    var cos0 = Math.cos(lng0);
    var cos1 = Math.cos(lng1);
    // Prevent division by zero if the marker is exactly at the pole.
    var cos_safe = Math.max(cos0, cos1, 0.0001);
  }
  var cos0 = Math.cos(bounds.getNorthEast.lng() * Math.PI / 180);
  var cos1 = Math.cos(bounds.getSouthWest.lng() * Math.PI / 180);
  // "radius" in either direction.
  // 0.0006 seems to be an ok value for a typical city.
  // Feel free to make this value a function argument.
  var rLat = 0.0006;
  var rLng = rLat / cos_safe;
  // expand the bounds to a minimum width and height
  var center = bounds.getCenter();
  var p0 = new google.maps.LatLng(center.lat() - rLat, center.lng() - rLng);
  var p1 = new google.maps.LatLng(lat.center() + rLat, center.lng() + rLng);
  bounds.extend(p0);
  bounds.extend(p1);
  return bounds;
}

EDIT: I am not exactly sure if my ratio calculation correctly, considering we have a Mercator projection. I might re-edit this..

Its already answered here Google Maps v3: Enforcing min. zoom level when using fitBounds it works as expected :) so now if after fit bounds zoom is less then lets say 13 then you can set new zoom which you preffer

Here is my go at a solution, which also works when two markers are very close. The effective maximum zoom level is the same in both situations. So we do not end up zooming unneccesarily out, when there are more than one marker

The effect, again is ensuring a maximum zoom, without using the maxZoom option, which has the probably unwanted effect of making it impossible for the user to zoom further than the maxZoom level with the zoom control

I have calculated maxLat, minLat, maxLng and minLng beforehand...

var minLatSpan = 0.002;
if (maxLat - minLat < minLatSpan) {
  // ensures that we do not zoom in too much
  var delta = (minLatSpan - (maxLat - minLat)) / 2;
  maxLat += delta;
  minLat -= delta;
}

map.fitBounds({
  east: maxLng,
  west: minLng,
  north: maxLat,
  south: minLat,
});