98 lines
3.0 KiB
JavaScript
98 lines
3.0 KiB
JavaScript
import {
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HALF_SIZE,
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MAX_SAFE_Y,
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fromEPSG4326,
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} from '../../../../src/ol/proj/epsg3857.js';
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import {
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addCommon,
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clearAllProjections,
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getPointResolution,
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get as getProjection,
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transform,
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} from '../../../../src/ol/proj.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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{
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g: [0, 0],
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m: [0, 0],
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},
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{
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g: [-180, -90],
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m: [-HALF_SIZE, -MAX_SAFE_Y],
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},
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{
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g: [180, 90],
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m: [HALF_SIZE, MAX_SAFE_Y],
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},
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{
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g: [-111.0429, 45.677],
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m: [-12361239.084208, 5728738.469095],
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},
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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(MAX_SAFE_Y, 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 https://docs.microsoft.com/en-us/bingmaps/articles/understanding-scale-and-resolution
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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)).to.roughlyEqual(
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19.11,
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1e-1
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);
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});
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it('returns the correct point scale at the latitude of Toronto', function () {
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// @see https://docs.microsoft.com/en-us/bingmaps/articles/understanding-scale-and-resolution
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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)).to.roughlyEqual(
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19.11 * Math.cos((Math.PI * 43.65) / 180),
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1e-9
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);
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});
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it('returns the correct point scale at various latitudes', function () {
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// @see https://docs.microsoft.com/en-us/bingmaps/articles/understanding-scale-and-resolution
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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)).to.roughlyEqual(
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19.11 * Math.cos((Math.PI * latitude) / 180),
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1e-9
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);
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}
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});
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});
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});
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