为什么从google文档中绘制地图需要50秒

为什么从谷歌文档中绘制地图需要50秒,我只有两列40行: 列是CITY,NAME。有些城市是重复的。根据firebug的说法,网络连接只需要2-3秒。所有的城市都在一个国家,我可以优化这个吗?

我的代码是:

  google.load('visualization', '1',
          {'packages': ['table', 'map']});
      google.setOnLoadCallback(initialize);

      function initialize() {
        // The URL here is the URL of the spreadsheet.
        // This is where the data is.
        var query = new google.visualization.Query(
            'http://spreadsheets.google.com/tq?key=xx');        
        query.send(draw);
      }

      function draw(response) {
        if (response.isError()) {
          alert('Error in query');
        }




        var geoView = new google.visualization.DataView(response.getDataTable());
        //geoView.setColumns([0, 1,2]);

        var table =
            new google.visualization.Table(document.getElementById('table_div'));
        table.draw(response.getDataTable(), {showRowNumber: false});

        var map =
            new google.visualization.Map(document.getElementById('map_div'));
        map.draw(geoView, {showTip: true});