Transformations

Transform coordinates between various coordinate systems used in Bulgaria.

Contents

• Transformations
  • Contents
  • Info
  • Install
    • Ellipsoids
    • Projections
  • Examples
    • Transform between geographic coordinates and projected in Lambert projection
    • Transform between geographic coordinates and projected in UTM
    • Transform between geographic coordinates and projected in Gauss–Krüger
    • Transform between geographic coordinates and projected in Web Mercator
    • Transform between geographic and geocentric coordinates
    • Transform between BGS coordinates
    • Format decimal degrees from/to degrees, minutes and seconds
  • Tests
  • License

Info

This project is based on Transformations.NET library.

The project can be used for transforming coordinates between various coordinate systems:

• BGS 1930
• BGS 1950
• BGS Sofia
• BGS 1970
• BGS 2005

Following projections are available:

• Lambert Conformal Conic with 2SP
• Universal Transverse Mercator
• Gauss–Krüger
• Spherical Web Mercator

You can transform between:

• Geographic coordinates
• Projected coordinates
• Geocentric coordinates

Transformations between BGS coordinate systems are done by calculating shift parameters from (precomputed grids). Grids are computed for both forward and reverse transformations. To construct the grids, 10 000 control points are transformed using official transformation engine, provided by the cadastral agency.

Install

You can install it with NPM (npm install transformations) or Yarn (yarn add transformations) and then import a desired transformation function:

import { transformGeographicToUTM } from 'transformations';

const input = [42.450682, 24.749747];
const result = transformGeographicToUTM(input);

Ellipsoids

import { ellipsoids } from 'transformations';

• GRS80 - GRS 1980
• BESSEL_1841 - Bessel 1841
• CLARKE_1866 - Clarke 1866
• EVEREST - Everest (Sabah and Sarawak)
• HELMERT - Helmert 1906
• HAYFORD - Hayford
• KRASSOVSKY - Krassovsky, 1942
• WALBECK - Walbeck
• WGS72 - WGS 1972
• WGS84 - WGS 1984
• SPHERE - Normal Sphere (R=6378137)

Projections

import { projections } from 'transformations';

• BGS_SOFIA - BGS Sofia. Local projection based on BGS 1950
• BGS_1930_24 - Gauss–Krüger projection based on Hayford ellipsoid
• BGS_1930_27 - Gauss–Krüger projection based on Hayford ellipsoid
• BGS_1950_3_24 - Gauss–Krüger projection based on Krassovsky ellipsoid
• BGS_1950_3_27 - Gauss–Krüger projection based on Krassovsky ellipsoid
• BGS_1950_6_21 - Gauss–Krüger projection based on Krassovsky ellipsoid
• BGS_1950_6_27 - Gauss–Krüger projection based on Krassovsky ellipsoid
• BGS_1970_K3 - ~ Northewest Bulgaria
• BGS_1970_K5 - ~ Southeast Bulgaria
• BGS_1970_K7 - ~ Northeast Bulgaria
• BGS_1970_K9 - ~ Southwest Bulgaria
• BGS_2005_KK - Lambert Conformal Conic with 2SP used by Cadastral Agency
• UTM34N - Universal Transverse Mercator zone 34 North
• UTM35N - Universal Transverse Mercator zone 35 North

Examples

Transform between geographic coordinates and projected in Lambert projection

import { transformGeographicToLambert, transformLambertToGeographic } from 'transformations';

let input = [42.7589996, 25.3799991];
let result = transformGeographicToLambert(input);
// result is: 4735953.342, 490177.508

let input = [4735953.349, 490177.508;
let result = transformLambertToGeographic(input);
// result is: 42.7589997, 25.3799991

Transform between geographic coordinates and projected in UTM

import { transformGeographicToUTM, transformUTMToGeographic } from 'transformations';

let input = [42.450682, 24.749747];
let result = transformGeographicToUTM(input);
// result is: 4702270.178, 314955.869

let input = [4702270.179, 314955.869];
let result = transformUTMToGeographic(input);
// result is: 42.450682, 24.749747

Transform between geographic coordinates and projected in Gauss–Krüger

import { transformGeographicToGauss, transformGaussToGeographic } from 'transformations';

let input = [42.7602978166667, 25.3824052611111];
let result = transformGeographicToGauss(input);
// result is: 4736629.503, 8613154.606

let input = [4736629.503, 8613154.607);
let result = transformGaussToGeographic(input);
// result is: 42.7602978, 25.38240528

Transform between geographic coordinates and projected in Web Mercator

import { transformGeographicToWebMercator, transformWebMercatorToGeographic } from 'transformations';

let input = [42.450682, 24.749747];
let result = transformGeographicToWebMercator(input);
// result is: 2755129.233, 5228730.328

let input = [2755129.23, 5228730.33];
let result = transformWebMercatorToGeographic(input);
// result is: 42.4506820, 24.7497470

Transform between geographic and geocentric coordinates

import { transformGeographicToGeocentric, transformGeocentricToGeographic } from 'transformations';

let input = [42.450682, 24.749747];
let result = transformGeographicToGeocentric(input);
// result is: X: 4280410.654, 1973273.422, 4282674.061

let input = [4280410.654, 1973273.422, 4282674.061];
let result = transformGeocentricToGeographic(input);
// result is: 42.450682, 24.749747

Transform between BGS coordinates

• BGS 1930

import { BGSCoordinates } from 'transformations';

const bgs = new BGSCoordinates();

let input = [4728966.163, 8607005.227];
let result = bgs.transform(input, projections.BGS_1930_24, projections.BGS_2005_KK);
// result is: 4728401.432, 483893.508

let input = [4728401.432, 483893.508];
let result = bgs.transform(input, projections.BGS_2005_KK, projections.BGS_1930_24);
// result is: 4728966.153, 8607005.214

• BGS 1950

import { BGSCoordinates } from 'transformations';

const bgs = new BGSCoordinates();

let input = [4729331.175, 8606933.614];
let result = bgs.transform(input, projections.BGS_1950_3_24, projections.BGS_2005_KK);
// result is: 4728401.442, 483893.521

let input = [4728401.432, 483893.508];
let result = tr.transform(input, projections.BGS_2005_KK, projections.BGS_1950_3_24);
// result is: 4729331.165, 8606933.601

• BGS Sofia

import { BGSCoordinates } from 'transformations';

const bgs = new BGSCoordinates();

let input = [48276.705, 45420.988];
let result = bgs.transform(input, projections.BGS_SOFIA, projections.BGS_2005_KK);
// result is: 4730215.221, 322402.929

let input = [4730215.229, 322402.935];
let result = bgs.transform(input, projections.BGS_2005_KK, projections.BGS_SOFIA);
// result is: 48276.713, 45420.993

• BGS 1970

import { BGSCoordinates } from 'transformations';

const bgs = new BGSCoordinates();

let input = [4725270.684, 8515734.475];
let result = bgs.transform(input, projections.BGS_1970_K3, projections.BGS_2005_KK);
// result is: 4816275.688, 332535.346

let input = [4816275.68, 332535.401];
let result = bgs.transform(input, projections.BGS_2005_KK, projections.BGS_1970_K3);
// result is: 4725270.677, 8515734.530

let input = [4613479.192, 9493233.633];
let result = bgs.transform(input, projections.BGS_1970_K5, projections.BGS_2005_KK);
// result is: 4679669.824, 569554.912

let input = [4679669.825, 569554.918];
let result = bgs.transform(input, projections.BGS_2005_KK, projections.BGS_1970_K5);
// result is: 4613479.193, 9493233.639

let input = [4708089.898, 9570974.988];
let result = bgs.transform(input, projections.BGS_1970_K7, projections.BGS_2005_KK);
// result is: 4810276.410, 626498.618

let input = [4810276.431, 626498.611];
let result = bgs.transform(input, projections.BGS_2005_KK, projections.BGS_1970_K7);
// result is: 4708089.919, 9570974.981

let input = [4547844.976, 8508858.179];
let result = bgs.transform(input, projections.BGS_1970_K9, projections.BGS_2005_KK);
// result is: 4675440.859, 330568.410

let input = [4675440.847, 330568.434];
let result = bgs.transform(input, projections.BGS_2005_KK, projections.BGS_1970_K9);
// result is: 4547844.965, 8508858.203

Format decimal degrees from/to degrees, minutes and seconds

import { convertDecimalDegreesToDMS, convertDMStoDecimalDegrees } from 'transformations';

let latitude = 42.336542;
let dms = convertDecimalDegreesToDMS(latitude);
// dms is: "422011.5512000000052"

let dms = '422011.5512000000052';
let result = convertDMStoDecimalDegrees(dms);
// result is: 42.336542

Tests

Check tests for more examples.

License

transformations is MIT License @ bojko108