GeoJSON

TIP

加载 GeoJSON 数据

代码如下:

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

<script lang="ts" setup>
import { onMounted, onBeforeUnmount } from "vue";
import Circle from "ol/geom/Circle";
import GeoJSON from "ol/format/GeoJSON";
import { View, Map, Feature } from "ol";
import { FeatureLike } from "ol/Feature";
import { Circle as CircleStyle, Fill, Stroke, Style } from "ol/style";
import { StyleLike } from "ol/style/Style";
import { XYZ, Vector as VectorSource } from "ol/source";
import { Tile as TileLayer, Vector as VectorLayer } from "ol/layer";
import { MAPURL, ATTRIBUTIONS } from "../../../constants";

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

const image = new CircleStyle({
  radius: 5,
  fill: undefined,
  stroke: new Stroke({ color: "red", width: 1 }),
});

const styles = {
  Point: new Style({
    image: image,
  }),
  LineString: new Style({
    stroke: new Stroke({
      color: "green",
      width: 1,
    }),
  }),
  MultiLineString: new Style({
    stroke: new Stroke({
      color: "green",
      width: 1,
    }),
  }),
  MultiPoint: new Style({
    image: image,
  }),
  MultiPolygon: new Style({
    stroke: new Stroke({
      color: "yellow",
      width: 1,
    }),
    fill: new Fill({
      color: "rgba(255, 255, 0, 0.1)",
    }),
  }),
  Polygon: new Style({
    stroke: new Stroke({
      color: "blue",
      lineDash: [4],
      width: 3,
    }),
    fill: new Fill({
      color: "rgba(0, 0, 255, 0.1)",
    }),
  }),
  GeometryCollection: new Style({
    stroke: new Stroke({
      color: "magenta",
      width: 2,
    }),
    fill: new Fill({
      color: "magenta",
    }),
    image: new CircleStyle({
      radius: 10,
      fill: undefined,
      stroke: new Stroke({
        color: "magenta",
      }),
    }),
  }),
  Circle: new Style({
    stroke: new Stroke({
      color: "red",
      width: 2,
    }),
    fill: new Fill({
      color: "rgba(255,0,0,0.2)",
    }),
  }),
};

const styleFunction: StyleLike = function (
  feature: FeatureLike
): Style | undefined {
  const geometry = feature.getGeometry();
  if (geometry) {
    return styles[geometry.getType()];
  }
};

const geojsonObject = {
  type: "FeatureCollection",
  crs: {
    type: "name",
    properties: {
      name: "EPSG:3857",
    },
  },
  features: [
    {
      type: "Feature",
      geometry: {
        type: "Point",
        coordinates: [0, 0],
      },
    },
    {
      type: "Feature",
      geometry: {
        type: "LineString",
        coordinates: [
          [4e6, -2e6],
          [8e6, 2e6],
        ],
      },
    },
    {
      type: "Feature",
      geometry: {
        type: "LineString",
        coordinates: [
          [4e6, 2e6],
          [8e6, -2e6],
        ],
      },
    },
    {
      type: "Feature",
      geometry: {
        type: "Polygon",
        coordinates: [
          [
            [-5e6, -1e6],
            [-3e6, -1e6],
            [-4e6, 1e6],
            [-5e6, -1e6],
          ],
        ],
      },
    },
    {
      type: "Feature",
      geometry: {
        type: "MultiLineString",
        coordinates: [
          [
            [-1e6, -7.5e5],
            [-1e6, 7.5e5],
          ],
          [
            [1e6, -7.5e5],
            [1e6, 7.5e5],
          ],
          [
            [-7.5e5, -1e6],
            [7.5e5, -1e6],
          ],
          [
            [-7.5e5, 1e6],
            [7.5e5, 1e6],
          ],
        ],
      },
    },
    {
      type: "Feature",
      geometry: {
        type: "MultiPolygon",
        coordinates: [
          [
            [
              [-5e6, 6e6],
              [-3e6, 6e6],
              [-3e6, 8e6],
              [-5e6, 8e6],
              [-5e6, 6e6],
            ],
          ],
          [
            [
              [-2e6, 6e6],
              [0, 6e6],
              [0, 8e6],
              [-2e6, 8e6],
              [-2e6, 6e6],
            ],
          ],
          [
            [
              [1e6, 6e6],
              [3e6, 6e6],
              [3e6, 8e6],
              [1e6, 8e6],
              [1e6, 6e6],
            ],
          ],
        ],
      },
    },
    {
      type: "Feature",
      geometry: {
        type: "GeometryCollection",
        geometries: [
          {
            type: "LineString",
            coordinates: [
              [-5e6, -5e6],
              [0, -5e6],
            ],
          },
          {
            type: "Point",
            coordinates: [4e6, -5e6],
          },
          {
            type: "Polygon",
            coordinates: [
              [
                [1e6, -6e6],
                [3e6, -6e6],
                [2e6, -4e6],
                [1e6, -6e6],
              ],
            ],
          },
        ],
      },
    },
  ],
};

const vectorSource = new VectorSource({
  features: new GeoJSON().readFeatures(geojsonObject),
});

vectorSource.addFeature(new Feature(new Circle([5e6, 7e6], 1e6)));

const vectorLayer = new VectorLayer({
  source: vectorSource,
  style: styleFunction,
});

let map: Map | null = null;
onMounted(() => {
  map = new Map({
    layers: [raster, vectorLayer],
    target: "map",
    view: new View({
      center: [0, 0],
      zoom: 2,
    }),
  });
});

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

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