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projection.EPSG3857 ​

projection.EPSG3857 is the Web Mercator projection object, mixing in projection.Common and measurer.WGS84Sphere. It converts geographical coordinates into meter-based Mercator planar coordinates and is maptalks' default projection (used by Google Maps / OSM). It is an object mixin with no standalone constructor.

js
import { projection } from "maptalks";

const p = projection.EPSG3857.project([116.39, 39.9]);
console.log(p.x, p.y); // meter-based projected coordinates

Properties / Static Methods ​

  • code: string — The projection code, 'EPSG:3857'.
  • maxLatitude: number — The maximum valid latitude, 85.0511287798.
  • metersPerDegree — Meters per degree, 6378137 * Math.PI / 180.
  • rad: number — The radian conversion factor, Math.PI / 180.

Methods ​

  • project(lnglat, out?): Coordinate — Web Mercator projection, converting lng/lat into meter-based projected coordinates.
  • unproject(p, out?): Coordinate — Web Mercator inverse projection, converting meter-based coordinates back to lng/lat.
  • Additionally inherits projectCoords / unprojectCoords / isSphere / isOutSphere / wrapCoord / getCircum / getSphereExtent from projection.Common.