geo-convert

Functions to convert from geographic coordinates (latitude and latitude) to UTM coordinates and vice verse.

Conversion between coordinates is performed using the proj4 library available at https://github.com/proj4js/proj4js.

Usage

File in ./dist/geo-convert.js accessible by namespace geoConvert in browser or ES5 environments.

git clone <...>
npm i
npm run build

Example

ES5 Environment

const geoConvert = require("geo-convert.js");

const coords = {
  latitude: 39.75621,
  longitude: -104.99404
};

const ll_to_utm = geoConvert.LLtoUTM(coords.longitude, coords.latitude);

const utm_to_ll = geoConvert.UTMtoLL(
  ll_to_utm.zone,
  ll_to_utm.easting,
  ll_to_utm.northing
);

console.log(ll_to_utm);
console.log(utm_to_ll);

ES6 Environment

import { LLtoUTM, UTMtoLL } from "geo-convert";

const coords = {
  latitude: 39.75621,
  longitude: -104.99404
};

const ll_to_utm = LLtoUTM(coords.longitude, coords.latitude);

const utm_to_ll = UTMtoLL(
  ll_to_utm.zone,
  ll_to_utm.easting,
  ll_to_utm.northing
);

console.log(ll_to_utm);
console.log(utm_to_ll);

Functions

• determineUtmZoneNumber(longitude, latitude)
• LLtoUTM(longitude, latitude, inCentimeters = false)
• UTMtoLL(zone, easting, northing)
  • easting and northing must be in meters

References

• proj4js
  • Used for converting between lon/lat to utm (and vice versa)
  • https://github.com/proj4js/proj4js
• mgrs
  • Some util code is extracted from here
  • https://github.com/proj4js/mgrs
• Openmap
  • Original code that mgrs uses
  • http://openmap-java.org/api/com/bbn/openmap/proj/coords/package-summary.html
• GeographicLib
  • https://geographiclib.sourceforge.io/
• Wikipedia
  • https://en.wikipedia.org/wiki/Universal_Transverse_Mercator_coordinate_system
  • https://en.wikipedia.org/wiki/Easting_and_northing