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iamvdo/index.js

Last active October 10, 2019 10:02
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Geo functions
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index.js
// Get Lat/Lng from Tile x,y,z
// (returns top/left corner of tile)
function tile2latlng (x, y, z) {
const n = Math.pow(2, z);
const lat = Math.atan(Math.sinh(Math.PI * (1 - 2 * y / n))) * 180 / Math.PI;
const lng = x / n * 360 - 180;
return { lat, lng };
}
// Get Tile x,y from Lat/Lng,z
function latlng2tile (lat, lng, z) {
const n = Math.pow(2, z);
const x = Math.floor((lng + 180) / 360 * n);
const y = Math.floor((1 - Math.log(Math.tan(lat * Math.PI / 180) + 1 / Math.cos(lat * Math.PI / 180)) / Math.PI) / 2 * n);
return { x, y };
}
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