<!DOCTYPE html>
<html ng-app="myApp">
<head>
<meta name="viewport" content="initial-scale=1.0, user-scalable=no" />
<script src="http://maps.google.com/maps/api/js?libraries=placeses,visualization,drawing,geometry,places"></script>
<script src="http://code.angularjs.org/1.3.15/angular.js"></script>
<script src="http://rawgit.com/allenhwkim/angularjs-google-maps/master/build/scripts/ng-map.js"></script>
<script>
  var app = angular.module('myApp', ['ngMap']);
  app.controller('CircleSimpleCtrl', function() {
    var vm = this;
    vm.cities = {
      chicago: {population:2714856, position: [41.878113, -87.629798]},
      newyork: {population:8405837, position: [40.714352, -74.005973]},
      losangeles: {population:3857799, position: [34.052234, -118.243684]},
      vancouver: {population:603502, position: [49.25, -123.1]},
    }
    vm.getRadius = function(num) {
      return Math.sqrt(num) * 100;
    }
    
    vm.tab = 1;
  });
</script>
</head>

<body ng-controller="CircleSimpleCtrl as vm">
  <button ng-click="vm.tab = 1">Tab 01</button>
  <button ng-click="vm.tab = 2">Tab 02</button>
  
  <div ng-if="vm.tab == 1">
    Just a placeholder div
  </div>
  
  <div ng-if="vm.tab == 2">
    <ng-map center="37.09024, -95.712891" zoom="4" mayTypeId="TERRAIN">
      <shape name="circle" ng-repeat="city in vm.cities" no-watcher="true"
        stroke-color="#FF0000"
        stroke-opacity="0.8"
        stroke-weight="2"
        fill-color="#FF0000"
        fill-opacity="0.35"
        center="{{city.position}}"
        radius="{{vm.getRadius(city.population)}}">
      </shape>
    </ng-map>
  </div>
  
  
</body>
</html>