Echarts参数属性学习：地图可视化视觉映射组件visualMap数组最大值max的获取方式

 function rondomNum(){
            return parseFloat(Math.random()*1000).toFixed(0);
        }

        var cityData = [
            {name: '阿克苏市', value: rondomNum()},
            {name: '温宿县', value: rondomNum()},
            {name: '库车县', value: rondomNum()},
            {name: '沙雅县', value: rondomNum()},
            {name: '新和县', value: rondomNum()},
            {name: '拜城县', value: rondomNum()},
            {name: '乌什县', value: rondomNum()},
            {name: '阿瓦提县', value: rondomNum()},
            {name: '柯坪县', value: rondomNum()},
            {name: '安康市', value: rondomNum()}
        ];

        var cityMax = cityData[0].value;
        for (var i = 0; i < cityData.length - 1; i++) {
            cityMax = cityMax < cityData[i + 1].value ? cityData[i + 1].value : cityMax
        }