极坐标双数值轴中画一个闭合的平滑曲线，怎样使首尾两点平滑连接？echarts 折线配置项内容和展示

画一个闭合的平滑曲线，怎样使首尾两点平滑连接？另外怎么使标签显示在曲线外或曲线内部不被曲线遮挡

      var data = [];

data.push([81.58, 0,1]);
data.push([88.34, 30,2]);
data.push([83.49, 60,3]);
data.push([67.84, 90,4]);
data.push([55.81, 120,5]);
data.push([73.68, 150,6]);
data.push([83.99, 180,7]);
data.push([85.93, 210,8]);
data.push([78.83, 240,9]);
data.push([65.78, 270,10]);
data.push([59.82, 300,11]);
data.push([69.40, 330,12]);
data.push([81.58, 360,1]);

option = {
    title: {
        text: '极坐标双数值轴'
    },
    legend: {
        data: ['line']
    },
    polar: {
        center: ['50%', '54%']
    },
    tooltip: {
        trigger: 'axis',
        axisPointer: {
            type: 'cross'
        }
    },
    angleAxis: {
        type: 'value',
        startAngle: 0
    },
    radiusAxis: {
        min: 0,
        show:false
    },
    series: [{
        coordinateSystem: 'polar',
        name: 'line',
        type: 'line',
        showSymbol: true,
        smooth:true,label: {
                normal: {
                    show: true
                },
                emphasis: {
                    show: true
                }
            },
            lableLine: {
                normal: {
                    show: false
                },
                emphasis: {
                    show: true
                }
            },
        data: data
    }],
    animationDuration: 2000
};