@ue-too/border / mercatorProjection

Function: mercatorProjection()

mercatorProjection(interestPoint, centerLongitude): Point

Defined in: projection.ts:49

Projects a geographic coordinate to Mercator projection.

Parameters

interestPoint

GeoCoord

The geographic coordinate to project

centerLongitude

number = 0

The central meridian in degrees (default: 0)

Returns

Point

The projected point in meters from the central meridian

Remarks

The Mercator projection is a cylindrical map projection that preserves angles and shapes locally. It's widely used for navigation because straight lines on the map represent constant bearings (rhumb lines).

The projection uses Earth's mean radius of 6,371,000 meters.

Note: The Mercator projection becomes increasingly distorted near the poles.

Example

const coord = { latitude: 51.5074, longitude: -0.1278 }; // London
const point = mercatorProjection(coord);
console.log(point); // { x: -14232.4, y: 6711665.7 }

// With custom center longitude
const pointCentered = mercatorProjection(coord, -0.1278);
console.log(pointCentered.x); // Close to 0