84 lines
2.8 KiB
JavaScript
84 lines
2.8 KiB
JavaScript
import {getPointResolution, transform, get as getProjection, clearAllProjections, addCommon} from '../../../../src/ol/proj.js';
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import {fromEPSG4326, HALF_SIZE} from '../../../../src/ol/proj/epsg3857.js';
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describe('ol/proj/epsg3857', function() {
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afterEach(function() {
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clearAllProjections();
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addCommon();
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});
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describe('fromEPSG4326()', function() {
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it('transforms from geographic to Web Mercator', function() {
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const tolerance = 1e-5;
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const cases = [{
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g: [0, 0],
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m: [0, 0]
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}, {
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g: [-180, -90],
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m: [-HALF_SIZE, -HALF_SIZE]
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}, {
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g: [180, 90],
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m: [HALF_SIZE, HALF_SIZE]
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}, {
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g: [-111.0429, 45.6770],
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m: [-12361239.084208, 5728738.469095]
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}];
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for (let i = 0, ii = cases.length; i < ii; ++i) {
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const point = cases[i].g;
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const transformed = fromEPSG4326(point);
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expect(transformed[0]).to.roughlyEqual(cases[i].m[0], tolerance);
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expect(transformed[1]).to.roughlyEqual(cases[i].m[1], tolerance);
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}
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});
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it('does not produce unexpected results for string coordinates', function() {
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const transformed = fromEPSG4326(['180', '90']);
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expect(transformed[0]).to.roughlyEqual(HALF_SIZE, 1e-5);
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expect(transformed[1]).to.roughlyEqual(HALF_SIZE, 1e-5);
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});
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});
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describe('getPointResolution', function() {
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it('returns the correct point scale at the equator', function() {
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// @see http://msdn.microsoft.com/en-us/library/aa940990.aspx
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const epsg3857 = getProjection('EPSG:3857');
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const resolution = 19.11;
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const point = [0, 0];
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expect(getPointResolution(epsg3857, resolution, point)).
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to.roughlyEqual(19.11, 1e-1);
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});
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it('returns the correct point scale at the latitude of Toronto',
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function() {
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// @see http://msdn.microsoft.com/en-us/library/aa940990.aspx
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const epsg3857 = getProjection('EPSG:3857');
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const epsg4326 = getProjection('EPSG:4326');
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const resolution = 19.11;
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const point = transform([0, 43.65], epsg4326, epsg3857);
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expect(getPointResolution(epsg3857, resolution, point)).
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to.roughlyEqual(19.11 * Math.cos(Math.PI * 43.65 / 180), 1e-9);
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});
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it('returns the correct point scale at various latitudes', function() {
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// @see http://msdn.microsoft.com/en-us/library/aa940990.aspx
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const epsg3857 = getProjection('EPSG:3857');
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const epsg4326 = getProjection('EPSG:4326');
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const resolution = 19.11;
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let latitude;
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for (latitude = 0; latitude <= 85; ++latitude) {
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const point = transform([0, latitude], epsg4326, epsg3857);
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expect(getPointResolution(epsg3857, resolution, point)).
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to.roughlyEqual(19.11 * Math.cos(Math.PI * latitude / 180), 1e-9);
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}
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});
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});
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});
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