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Question

Random marker within a rectangular bounds?

Answer 1

+1 A:

You may want to try the following:

function getRandom_marker(bounds) {
  var lat_min = bounds.getSouthWest().lat(),
      lat_range = bounds.getNorthEast().lat() - lat_min,
      lng_min = bounds.getSouthWest().lng(),
      lng_range = bounds.getNorthEast().lng() - lng_min;

  return new google.maps.LatLng(lat_min + (Math.random() * lat_range), 
                                lng_min + (Math.random() * lng_range));
}

Complete example:

<!DOCTYPE html>
<html> 
<head> 
   <meta http-equiv="content-type" content="text/html; charset=UTF-8"/> 
   <title>Google Maps Random Points Demo</title> 
   <script src="http://maps.google.com/maps/api/js?sensor=false" 
           type="text/javascript"></script> 
</head> 
<body> 
   <div id="map" style="width: 400px; height: 300px;"></div> 

   <script type="text/javascript"> 

   function getRandom_marker(bounds) {
     var lat_min = bounds.getSouthWest().lat(),
         lat_range = bounds.getNorthEast().lat() - lat_min,
         lng_min = bounds.getSouthWest().lng(),
         lng_range = bounds.getNorthEast().lng() - lng_min;

     return new google.maps.LatLng(lat_min + (Math.random() * lat_range), 
                                   lng_min + (Math.random() * lng_range));
   }

   var map = new google.maps.Map(document.getElementById('map'), {
     zoom: 8,
     center: new google.maps.LatLng(-34.397, 150.644),
     mapTypeId: google.maps.MapTypeId.ROADMAP
   });

   google.maps.event.addListener(map, 'tilesloaded', function () {
     var mapBounds = map.getBounds();

     for (var i = 0; i < 20; i++) {
       new google.maps.Marker({
         position: getRandom_marker(mapBounds), 
         map: map
       });   
     }
   });

   </script> 
</body>

Screenshot:

Random Markers

Daniel Vassallo 2010-09-06 02:00:41

@ Daniel ,i think use the Math.abs is not right, because lat,lng has Negative number ,look my updated.

zjm1126 2010-09-06 02:29:26

@zjm1126: You're right, it's not necessary, since North will always be bigger than South, and West bigger than East. Fixing my answer.

Daniel Vassallo 2010-09-06 02:38:03

your second code doesn't changed . also has Math.abs

zjm1126 2010-09-06 02:53:06

@zjm1126: Fixed :)

Daniel Vassallo 2010-09-06 11:21:44

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Random marker within a rectangular bounds?

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