@scratching-platypus/geodesy-ts

Vincenty’s formula in TypeScript for computing distances and azimuths between geographic coordinates.

Install

npm install @scratching-platypus/geodesy-ts

Types

export type Ellipsoid = {
    a: number; // semi-major axis
    b: number; // semi-minor axis
    f: number; // flattening
};

type GeodesicForwardResult = {
    coordinate: Coordinate; // target coordinate
    finalAzimuth: number; // target direction
};

type GeodesicInverseResult = {
    distance: number; // distance between A and B (meters)
    initialAzimuth: number; // azimuth A -> B (degrees)
    finalAzimuth: number; // azimuth B -> A (degrees)
};

Coordinate is provided by @scratching-platypus/coordinate-ts

Geodesy

All geodesic functions accept an optional ellipsoid parameter. If omitted, the WGS84 ellipsoid is used by default.

import { vincentyInverse } from "@scratching-platypus/geodesy-ts";

vincentyInverse(A, B)                       // implicit WGS84
vincentyInverse(A, B, GRS80)                // custom ellipsoid
vincentyInverse(A, B, { a: 1: b: 1: f: 0 }) // sphere

import { vincentyForward } from "@scratching-platypus/geodesy-ts";

vincentyForward(A, initialAzimuth, direction)                       // implicit WGS84
vincentyForward(A, initialAzimuth, direction, GRS80)                // custom ellipsoid
vincentyForward(A, initialAzimuth, direction, { a: 1: b: 1: f: 0 }) // sphere