绘制同心圆

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绘制同心圆示例。
代码如下:

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vue
<template>
  <div class="top-bar">
    <el-button type="primary" @click="addMultiCircle">添加同心圆</el-button>
  </div>
  <div id="map"></div>
</template>

<script lang="ts" setup>
import { onMounted, onBeforeUnmount } from "vue";
import L from "leaflet";
import { ATTRIBUTIONS } from "../../../constants";

let map: L.Map | null = null;
const initMap = () => {
  //地图容器
  map = L.map("map", {
    //参考坐标系
    crs: L.CRS.EPSG3857,
    //显示中心
    center: [30.5217, 114.3948],
    //当前显示等级
    zoom: 18,
  });

  //加载天地图矢量图层
  L.tileLayer(
    "http://t0.tianditu.gov.cn/DataServer?T=vec_w&x={x}&y={y}&l={z}&tk=55b4d4eaef95384c946e9bd1b99c5610",
    { noWrap: true, attribution: ATTRIBUTIONS }
  ).addTo(map);
  //加载天地图矢量注记图层
  L.tileLayer(
    "http://t0.tianditu.gov.cn/DataServer?T=cva_w&x={x}&y={y}&l={z}&tk=55b4d4eaef95384c946e9bd1b99c5610",
    { noWrap: true, attribution: ATTRIBUTIONS }
  ).addTo(map);
};

onMounted(() => {
  initMap();
});

// 销毁地图
onBeforeUnmount(() => {
  if (map) {
    map.remove();
    map = null;
  }
});

/**添加同心圆
 */
function addMultiCircle() {
  if (!map) return;
  //设置圆心坐标
  const latLng = L.latLng(30.5217, 114.3948);
  //初始半径
  let r = 65;
  for (let i = 0; i < 5; i++) {
    //添加圆
    L.circle(latLng, {
      //圆半径
      radius: r,
      //颜色
      color: "#ffcc33",
      //填充色
      fillColor: "white",
      //填充色透明度
      fillOpacity: 0.8,
    }).addTo(map);
    //调整半径大小
    r = r / 1.5;
  }
}
</script>

<!-- Add "scoped" attribute to limit CSS to this component only -->
<style scoped>
#map {
  height: 650px;
  color: #3a3a3a;
}
.top-bar {
  height: 50px;
  line-height: 30px;
  text-align: center;
}
</style>
绘制同心圆 ​

代码如下: ​

绘制同心圆

代码如下:
