openlayers/examples/geojson.js

import Feature from 'ol/Feature';
import Map from 'ol/Map';
import View from 'ol/View';
import GeoJSON from 'ol/format/GeoJSON';
import Circle from 'ol/geom/Circle';
import {Tile as TileLayer, Vector as VectorLayer} from 'ol/layer';
import {OSM, Vector as VectorSource} from 'ol/source';
import {Circle as CircleStyle, Fill, Stroke, Style} from 'ol/style';


const image = new CircleStyle({
  radius: 5,
  fill: null,
  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: null,
      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 = function(feature) {
  return styles[feature.getGeometry().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], [-4e6, 1e6], [-3e6, -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], [-5e6, 8e6], [-3e6, 8e6], [-3e6, 6e6]]],
        [[[-2e6, 6e6], [-2e6, 8e6], [0, 8e6], [0, 6e6]]],
        [[[1e6, 6e6], [1e6, 8e6], [3e6, 8e6], [3e6, 6e6]]]
      ]
    }
  }, {
    'type': 'Feature',
    'geometry': {
      'type': 'GeometryCollection',
      'geometries': [{
        'type': 'LineString',
        'coordinates': [[-5e6, -5e6], [0, -5e6]]
      }, {
        'type': 'Point',
        'coordinates': [4e6, -5e6]
      }, {
        'type': 'Polygon',
        'coordinates': [[[1e6, -6e6], [2e6, -4e6], [3e6, -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
});

const map = new Map({
  layers: [
    new TileLayer({
      source: new OSM()
    }),
    vectorLayer
  ],
  target: 'map',
  view: new View({
    center: [0, 0],
    zoom: 2
  })
});