74 lines
2.2 KiB
JavaScript
74 lines
2.2 KiB
JavaScript
import Map from '../src/ol/Map.js';
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import View from '../src/ol/View.js';
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import KML from '../src/ol/format/KML.js';
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import Polygon from '../src/ol/geom/Polygon.js';
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import {Tile as TileLayer, Vector as VectorLayer} from '../src/ol/layer.js';
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import {toContext} from '../src/ol/render.js';
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import Stamen from '../src/ol/source/Stamen.js';
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import VectorSource from '../src/ol/source/Vector.js';
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import {Fill, Icon, Stroke, Style} from '../src/ol/style.js';
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const symbol = [[0, 0], [4, 2], [6, 0], [10, 5], [6, 3], [4, 5], [0, 0]];
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let scale;
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const scaleFunction = function(coordinate) {
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return [coordinate[0] * scale, coordinate[1] * scale];
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};
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const styleCache = {};
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const styleFunction = function(feature) {
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// 2012_Earthquakes_Mag5.kml stores the magnitude of each earthquake in a
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// standards-violating <magnitude> tag in each Placemark. We extract it from
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// the Placemark's name instead.
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const name = feature.get('name');
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const magnitude = parseFloat(name.substr(2));
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const size = parseInt(10 + 40 * (magnitude - 5), 10);
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scale = size / 10;
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let style = styleCache[size];
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if (!style) {
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const canvas = /** @type {HTMLCanvasElement} */ (document.createElement('canvas'));
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const vectorContext = toContext(
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/** @type {CanvasRenderingContext2D} */ (canvas.getContext('2d')),
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{size: [size, size], pixelRatio: 1});
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vectorContext.setStyle(new Style({
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fill: new Fill({color: 'rgba(255, 153, 0, 0.4)'}),
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stroke: new Stroke({color: 'rgba(255, 204, 0, 0.2)', width: 2})
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}));
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vectorContext.drawGeometry(new Polygon([symbol.map(scaleFunction)]));
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style = new Style({
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image: new Icon({
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img: canvas,
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imgSize: [size, size],
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rotation: 1.2
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})
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});
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styleCache[size] = style;
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}
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return style;
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};
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const vector = new VectorLayer({
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source: new VectorSource({
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url: 'data/kml/2012_Earthquakes_Mag5.kml',
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format: new KML({
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extractStyles: false
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})
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}),
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style: styleFunction
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});
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const raster = new TileLayer({
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source: new Stamen({
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layer: 'toner'
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})
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});
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const map = new Map({
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layers: [raster, vector],
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target: 'map',
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view: new View({
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center: [0, 0],
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zoom: 2
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})
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});
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