比例尺控件

TIP

缩放地图可以看到比例尺的大小跟随着变化。

代码如下:

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vue

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

<script lang="ts" setup>
import { onMounted, onBeforeUnmount } from "vue";
import { Map, View } from "ol";
import { Tile as TileLayer } from "ol/layer";
import { ScaleLine, defaults } from "ol/control";
import { XYZ } from "ol/source";
import { MAPURL, ATTRIBUTIONS } from "../../../constants";

const raster = new TileLayer({
  source: new XYZ({
    attributions: ATTRIBUTIONS,
    url: MAPURL,
    maxZoom: 20,
  }),
});

//实例化比例尺控件（ScaleLine）
const scaleLineControl = new ScaleLine({
  //设置比例尺单位，degrees、imperial、us、nautical、metric（度量单位）
  units: "metric",
});

let map: Map | null = null;
const initMap = () => {
  map = new Map({
    //初始化map
    target: "map",
    //地图容器中加载的图层
    layers: [
      //加载瓦片图层数据
      raster,
    ],
    view: new View({
      projection: "EPSG:4326", // 坐标系，有EPSG:4326和EPSG:3 857
      center: [0, 0],
      //地图初始显示级别
      zoom: 5,
    }),
    //加载控件到地图容器中
    //加载比例尺控件
    controls: defaults().extend([scaleLineControl]),
  });
};
onMounted(() => {
  initMap();
});

onBeforeUnmount(() => {
  if (map) {
    map.dispose();
    map = null;
  }
});
</script>

<!-- Add "scoped" attribute to limit CSS to this component only -->
<style scoped>
#map {
  width: 100%;
  height: 650px;
}
</style>

比例尺控件 ​

代码如下: ​

比例尺控件

代码如下: