72 lines
1.8 KiB
JavaScript
72 lines
1.8 KiB
JavaScript
import GeoTIFF from '../src/ol/source/GeoTIFF.js';
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import LayerGroup from '../src/ol/layer/Group.js';
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import Map from '../src/ol/Map.js';
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import TileGrid from '../src/ol/tilegrid/TileGrid.js';
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import View from '../src/ol/View.js';
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import WebGLTileLayer from '../src/ol/layer/WebGLTile.js';
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import {getIntersection} from '../src/ol/extent.js';
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// Metadata from https://s2downloads.eox.at/demo/EOxCloudless/2019/rgb/2019_EOxCloudless_rgb.json
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// Tile grid of the GeoTIFF pyramid layout
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const tileGrid = new TileGrid({
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origin: [-180, 90],
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resolutions: [0.703125, 0.3515625, 0.17578125, 8.7890625e-2, 4.39453125e-2],
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tileSizes: [
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[512, 256],
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[1024, 512],
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[2048, 1024],
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[4096, 2048],
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[4096, 4096],
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],
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});
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const pyramid = new LayerGroup();
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const layerForUrl = {};
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const zs = tileGrid.getResolutions().length;
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function useLayer(z, x, y) {
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const url = `https://s2downloads.eox.at/demo/EOxCloudless/2019/rgb/${z}/${y}/${x}.tif`;
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if (!(url in layerForUrl)) {
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pyramid.getLayers().push(
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new WebGLTileLayer({
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minZoom: z,
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maxZoom: z === 0 || z === zs - 1 ? undefined : z + 1,
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extent: tileGrid.getTileCoordExtent([z, x, y]),
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source: new GeoTIFF({
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sources: [
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{
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url: url,
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},
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],
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}),
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})
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);
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layerForUrl[url] = true;
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}
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}
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const map = new Map({
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target: 'map',
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layers: [pyramid],
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view: new View({
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projection: 'EPSG:4326',
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center: [0, 0],
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zoom: 0,
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showFullExtent: true,
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}),
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});
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// Add overview layer
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useLayer(0, 0, 0);
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// Add layer for specific extent on demand
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map.on('moveend', () => {
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const view = map.getView();
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tileGrid.forEachTileCoord(
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getIntersection([-180, -90, 180, 90], view.calculateExtent()),
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tileGrid.getZForResolution(view.getResolution()),
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([z, x, y]) => useLayer(z, x, y)
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);
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});
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