122 lines
3.4 KiB
JavaScript
122 lines
3.4 KiB
JavaScript
import GeoJSON from '../src/ol/format/GeoJSON.js';
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import Map from '../src/ol/Map.js';
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import VectorLayer from '../src/ol/layer/Vector.js';
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import VectorSource from '../src/ol/source/Vector.js';
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import View from '../src/ol/View.js';
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import {DragBox, Select} from '../src/ol/interaction.js';
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import {Fill, Stroke, Style} from '../src/ol/style.js';
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import {platformModifierKeyOnly} from '../src/ol/events/condition.js';
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const vectorSource = new VectorSource({
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url: 'https://openlayers.org/data/vector/ecoregions.json',
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format: new GeoJSON(),
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});
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const style = new Style({
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fill: new Fill({
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color: '#eeeeee',
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}),
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});
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const map = new Map({
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layers: [
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new VectorLayer({
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source: vectorSource,
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background: '#1a2b39',
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style: function (feature) {
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const color = feature.get('COLOR_BIO') || '#eeeeee';
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style.getFill().setColor(color);
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return style;
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},
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}),
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],
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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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constrainRotation: 16,
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}),
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});
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const selectedStyle = new Style({
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fill: new Fill({
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color: 'rgba(255, 255, 255, 0.6)',
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}),
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stroke: new Stroke({
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color: 'rgba(255, 255, 255, 0.7)',
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width: 2,
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}),
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});
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// a normal select interaction to handle click
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const select = new Select({
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style: function (feature) {
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const color = feature.get('COLOR_BIO') || '#eeeeee';
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selectedStyle.getFill().setColor(color);
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return selectedStyle;
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},
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});
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map.addInteraction(select);
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const selectedFeatures = select.getFeatures();
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// a DragBox interaction used to select features by drawing boxes
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const dragBox = new DragBox({
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condition: platformModifierKeyOnly,
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});
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map.addInteraction(dragBox);
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dragBox.on('boxend', function () {
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// features that intersect the box geometry are added to the
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// collection of selected features
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// if the view is not obliquely rotated the box geometry and
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// its extent are equalivalent so intersecting features can
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// be added directly to the collection
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const rotation = map.getView().getRotation();
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const oblique = rotation % (Math.PI / 2) !== 0;
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const candidateFeatures = oblique ? [] : selectedFeatures;
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const extent = dragBox.getGeometry().getExtent();
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vectorSource.forEachFeatureIntersectingExtent(extent, function (feature) {
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candidateFeatures.push(feature);
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});
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// when the view is obliquely rotated the box extent will
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// exceed its geometry so both the box and the candidate
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// feature geometries are rotated around a common anchor
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// to confirm that, with the box geometry aligned with its
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// extent, the geometries intersect
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if (oblique) {
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const anchor = [0, 0];
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const geometry = dragBox.getGeometry().clone();
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geometry.rotate(-rotation, anchor);
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const extent = geometry.getExtent();
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candidateFeatures.forEach(function (feature) {
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const geometry = feature.getGeometry().clone();
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geometry.rotate(-rotation, anchor);
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if (geometry.intersectsExtent(extent)) {
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selectedFeatures.push(feature);
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}
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});
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}
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});
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// clear selection when drawing a new box and when clicking on the map
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dragBox.on('boxstart', function () {
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selectedFeatures.clear();
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});
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const infoBox = document.getElementById('info');
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selectedFeatures.on(['add', 'remove'], function () {
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const names = selectedFeatures.getArray().map(function (feature) {
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return feature.get('ECO_NAME');
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});
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if (names.length > 0) {
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infoBox.innerHTML = names.join(', ');
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} else {
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infoBox.innerHTML = 'None';
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}
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});
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