Nimble Pixie Merchant

    transformations

    1.2.0 • Public • Published

    Transformations

    Transform coordinates between various coordinate systems used in Bulgaria.

    Contents

    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 (there can be no control points near by if the point is close to the zone's border)
    • 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 transformation parameters using TPS or Affine transformation based on predefined control points (ControlPoints namespace). You can control what type of transformation is used by passing useTPS boolean parameter to BGSCoordinates.transform(). All other transformations are done directly as the transformation parameters are known. Precision is arround 10cm.

    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

    Transform points in extent

    Use this method to calculate transformation parameters once and apply them to all input points.

    You can either pass an extent, for which the transformation parameters will be calculated:

    let extent = [4515891.16322039, 8471284.82458501, 4565579.62520789, 8551929.53794741];
    let result = bgs.transformArray([...], projections.BGS_1970_K9, projections.BGS_2005_KK, true, extent);

    or just pass the points and use the bounding extent:

    let result = bgs.transformArray([...], projections.BGS_1970_K9, projections.BGS_2005_KK, true);

    *Use TPS transformation as it gives better accuracy.

    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

    Dependencies

    Tests

    Check tests for more examples.

    License

    transformations is MIT License @ bojko108

    Install

    npm i transformations

    DownloadsWeekly Downloads

    2

    Version

    1.2.0

    License

    MIT

    Unpacked Size

    2.02 MB

    Total Files

    41

    Last publish

    Collaborators

    • bojko108