请教echarts地图自定义标点的问题

想请教下各位大佬：
①echarts怎样才能将地图上原本的蓝色圆点替换成五角星？我搜索了很多文档说替换为star即可，但是我在地图实例里测试并没有用。。
②需求是当前数据若≤最低价才将五角星标上，这个有自定义方法吗？

求指教求代码示例。。。急在线等

参考这个示例：http://www.echartsjs.com/gallery/editor.html?c=geo-map-scatter

坐标系改为geo，配置symbol为图片地址就行了，默认的配置没有星星的。。
http://echarts.baidu.com/option.html#series-scatter.symbol

显示不显示五角星自己整好数据，小于你的最低价才添加数据就行了

  symbol: 'image://data:image/gif;base64,R0lGODlhEAAQAMQAAORHHOVSKudfOulrSOp3WOyDZu6QdvCchPGolfO0o/XBs/fNwfjZ0frl3/zy7////wAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACH5BAkAABAALAAAAAAQABAAAAVVICSOZGlCQAosJ6mu7fiyZeKqNKToQGDsM8hBADgUXoGAiqhSvp5QAnQKGIgUhwFUYLCVDFCrKUE1lBavAViFIDlTImbKC5Gm2hB0SlBCBMQiB0UjIQA7',

你可以访问上面的地址，将下面的代码贴入左边的输入框运行下就看到效果了

var data = [
    {name: '海门', value: 9},
    {name: '鄂尔多斯', value: 12},
    {name: '招远', value: 12},
    {name: '舟山', value: 12},
    {name: '齐齐哈尔', value: 14},
    {name: '盐城', value: 15},
    {name: '赤峰', value: 16},
];

var geoCoordMap = {
   '海门':[121.15,31.89],
   '鄂尔多斯':[109.781327,39.608266],
   '招远':[120.38,37.35],
   '舟山':[122.207216,29.985295],
   '齐齐哈尔':[123.97,47.33],
   '盐城':[120.13,33.38],
   '赤峰':[118.87,42.28],
   '青岛':[120.33,36.07],
   '乳山':[121.52,36.89],
   '金昌':[102.188043,38.520089],
   '泉州':[118.58,24.93],
   '莱西':[120.53,36.86],
   '日照':[119.46,35.42],
   '胶南':[119.97,35.88],
   '南通':[121.05,32.08],
   '拉萨':[91.11,29.97],
   '云浮':[112.02,22.93],
   '梅州':[116.1,24.55],
   '文登':[122.05,37.2],
   '上海':[121.48,31.22],
   '攀枝花':[101.718637,26.582347],
   '威海':[122.1,37.5],
   '承德':[117.93,40.97],
   '厦门':[118.1,24.46],
   '汕尾':[115.375279,22.786211],
   '潮州':[116.63,23.68],
   '丹东':[124.37,40.13],
   '太仓':[121.1,31.45],
   '曲靖':[103.79,25.51],
   '烟台':[121.39,37.52],
};

function convertData(data) {
   var res = [];
   for (var i = 0; i < data.length; i++) {
       var geoCoord = geoCoordMap[data[i].name];
       if (geoCoord) {
           res.push({
               name: data[i].name,
               value: geoCoord.concat(data[i].value)
           });
       }
   }
   return res;
}

function randomValue() {
    return Math.round(Math.random()*1000);
}



option = {
    tooltip: {},
    visualMap: {
        min: 0,
        max: 1500,
        left: 'left',
        top: 'bottom',
        text: ['High','Low'],
        seriesIndex: [1],
        inRange: {
            color: ['#e0ffff', '#006edd']
        },
        calculable : true
    },
    geo: {
        map: 'china',
        roam: true,
        label: {
            normal: {
                show: true,
                textStyle: {
                    color: 'rgba(0,0,0,0.4)'
                }
            }
        },
        itemStyle: {
            normal:{
                borderColor: 'rgba(0, 0, 0, 0.2)'
            }
        }
    },
    series : [
       {
           type: 'scatter',
           coordinateSystem: 'geo',
           data: convertData(data),
           symbolSize: 20,
           symbol: 'image://data:image/gif;base64,R0lGODlhEAAQAMQAAORHHOVSKudfOulrSOp3WOyDZu6QdvCchPGolfO0o/XBs/fNwfjZ0frl3/zy7////wAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACH5BAkAABAALAAAAAAQABAAAAVVICSOZGlCQAosJ6mu7fiyZeKqNKToQGDsM8hBADgUXoGAiqhSvp5QAnQKGIgUhwFUYLCVDFCrKUE1lBavAViFIDlTImbKC5Gm2hB0SlBCBMQiB0UjIQA7',

           label: {
               normal: {
                   formatter: '{b}',
                   position: 'right',
                   show: false
               },
               emphasis: {
                   show: true
               }
           },
           itemStyle: {
               normal: {
                    color: '#F06C00'
               }
           }
        }
    ]
};