图层探查

TIP

图层探查示例。

代码如下:

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<template>
  <div id="map"></div>
</template>

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

let map: L.Map | null = null;
const initMap = () => {
  //地图容器
  map = L.map("map", {
    zoomControl: false,
    //参考坐标系
    crs: L.CRS.EPSG3857,
    //显示中心
    center: [22.548857, 114.064839],
    //最小显示等级
    minZoom: 1,
    //最大显示等级
    maxZoom: 18,
    //当前显示等级
    zoom: 10,
    //限制显示地理范围
    maxBounds: L.latLngBounds(L.latLng(-180, -180), L.latLng(180, 180)),
  });
  //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);
  //创建天地图影像图层
  const imgLayer = L.tileLayer(
    "http://t0.tianditu.gov.cn/DataServer?T=img_w&x={x}&y={y}&l={z}&tk=55b4d4eaef95384c946e9bd1b99c5610",
    { noWrap: true, attribution: ATTRIBUTIONS }
  );
  //添加放大镜
  L.magnifyingGlass({
    //设置放大镜中显示的图层
    layers: [imgLayer],
    //探查半径
    radius: 100,
    //设置放大镜中图层级数和主图层的级数差（0表示同级）
    zoomOffset: 0,
  }).addTo(map);
};

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

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

<!-- Add "scoped" attribute to limit CSS to this component only -->
<style scoped>
#map {
  height: 650px;
  color: #3a3a3a;
}
</style>

参考文档:

leaflet.magnifyingglass