@ue-too/border / index / mercatorProjection

関数: mercatorProjection()

mercatorProjection(interestPoint, centerLongitude): Point

定義: projection.ts:49

Projects a geographic coordinate to Mercator projection.

パラメータ

interestPoint

GeoCoord

The geographic coordinate to project

centerLongitude

number = 0

The central meridian in degrees (default: 0)

戻り値

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.

例

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