Files
openlayers/examples/turf.js
2018-04-24 09:06:30 -06:00

55 lines
1.6 KiB
JavaScript

// NOCOMPILE
// this example uses turf.js for which we don't have an externs file.
import Map from '../src/ol/Map.js';
import View from '../src/ol/View.js';
import GeoJSON from '../src/ol/format/GeoJSON.js';
import {Tile as TileLayer, Vector as VectorLayer} from '../src/ol/layer.js';
import {fromLonLat} from '../src/ol/proj.js';
import {OSM, Vector as VectorSource} from '../src/ol/source.js';
const source = new VectorSource();
fetch('data/geojson/roads-seoul.geojson').then(function(response) {
return response.json();
}).then(function(json) {
const format = new GeoJSON();
const features = format.readFeatures(json);
const street = features[0];
// convert to a turf.js feature
const turfLine = format.writeFeatureObject(street);
// show a marker every 200 meters
const distance = 0.2;
// get the line length in kilometers
const length = turf.lineDistance(turfLine, 'kilometers');
for (let i = 1; i <= length / distance; i++) {
const turfPoint = turf.along(turfLine, i * distance, 'kilometers');
// convert the generated point to a OpenLayers feature
const marker = format.readFeature(turfPoint);
marker.getGeometry().transform('EPSG:4326', 'EPSG:3857');
source.addFeature(marker);
}
street.getGeometry().transform('EPSG:4326', 'EPSG:3857');
source.addFeature(street);
});
const vectorLayer = new VectorLayer({
source: source
});
const rasterLayer = new TileLayer({
source: new OSM()
});
const map = new Map({
layers: [rasterLayer, vectorLayer],
target: document.getElementById('map'),
view: new View({
center: fromLonLat([126.980366, 37.526540]),
zoom: 15
})
});