echarts category配置项内容和展示

      
    function randomData() {
        return Math.round(Math.random()*2500);
    }

    option = {
        tooltip: {
            trigger: 'item',
            formatter: '{b}:{c}'
        },
        visualMap: {
            seriesIndex: 0,
            min: 0,
            max: 2500,
            left: 'left',
            top: 'bottom',
            text: ['高','低'], 
            // 文本，默认为数值文本
            color:['#0b97cb','#e8b489'],
            calculable: true
        },
        grid: {
            height: 200,
            width: 8,
            right: 80,
            bottom: 10
        },
        xAxis: {
            type: 'category',
            data: [],
            splitNumber: 1,
            show: false
        },
        yAxis: {
            position: 'right',
            min: 0,
            max: 20,
            splitNumber: 20,
            inverse: true,
            axisLabel: {
                show: true
            },
            axisLine: {
                show: false
            },
            splitLine: {
                show: false
            },
            axisTick: {
                show: false
            },
            data: []
        },
        series: [
            {
                zlevel: 1,
                name: '中国',
                type: 'map',
                mapType: 'china',
                selectedMode : 'multiple',
                roam: true,
                left: 0,
                right: '15%',
                label: {
                    normal: {
                        show: true
                    },
                    emphasis: {
                        show: true
                    }
                },
                data:[
                    {name: '北京',value: randomData() },
                    {name: '天津',value: randomData() },
                    {name: '上海',value: randomData() },
                    {name: '重庆',value: randomData() },
                    {name: '河北',value: randomData() },
                    {name: '河南',value: randomData() },
                    {name: '云南',value: randomData() },
                    {name: '辽宁',value: randomData() },
                    {name: '黑龙江',value: randomData() },
                    {name: '湖南',value: randomData() },
                    {name: '安徽',value: randomData() },
                    {name: '山东',value: randomData() },
                    {name: '新疆',value: randomData() },
                    {name: '江苏',value: randomData() },
                    {name: '浙江',value: randomData() },
                    {name: '江西',value: randomData() },
                    {name: '湖北',value: randomData() },
                    {name: '广西',value: randomData() },
                    {name: '甘肃',value: randomData() },
                    {name: '山西',value: randomData() },
                    {name: '内蒙古',value: randomData() },
                    {name: '陕西',value: randomData() },
                    {name: '吉林',value: randomData() },
                    {name: '福建',value: randomData() },
                    {name: '贵州',value: randomData() },
                    {name: '广东',value: randomData() },
                    {name: '青海',value: randomData() },
                    {name: '西藏',value: randomData() },
                    {name: '四川',value: randomData() },
                    {name: '宁夏',value: randomData() },
                    {name: '海南',value: randomData() },
                    {name: '台湾',value: randomData() },
                    {name: '香港',value: randomData() },
                    {name: '澳门',value: randomData() }
                ]
            },
            {
                zlevel: 2,
                name: '地图指示',
                type: 'bar',
                barWidth: 5,
                itemStyle: {
                    normal: {
                        color: undefined,
                        shadowColor: 'rgba(0, 0, 0, 0.1)',
                        shadowBlur: 10
                    }
                },
                data: [20]
            }
        ]
    };