地图中以中心点画半径

var map = new AMap.Map('container', {
    resizeEnable: true,
    zoom:11,
    center: [118.778287, 31.972822]
});
    // 构造点标记
var marker = new AMap.Marker({
    icon: "https://webapi.amap.com/theme/v1.3/markers/n/mark_b.png",
    position: [118.778287, 31.972822]
});
// 构造矢量圆形
var circle = new AMap.Circle({
    center: new AMap.LngLat("118.778287", "31.972822"), // 圆心位置
    radius: 24000,  //半径
    strokeColor: "#F33",  //线颜色
    strokeOpacity: 1,  //线透明度
    strokeWeight: 1,  //线粗细度
    fillColor: "#ee2200",  //填充颜色
    fillOpacity: 0.1 //填充透明度
});