nakarte

index.js (4022B)

---

 // Conversion methods from EPSG Geomatics Guidance Note number 7, part 2 – September 2019
 
 /* eslint-disable camelcase */
 // EPSG 4284
 const ellipsoidKrassowsky1940 = {
     a: 6378245,
     inv_f: 298.3,
 };
 
 // EPSG 4326
 const ellipsoidWGS1984 = {
     a: 6378137,
     inv_f: 298.257223563,
 };
 
 // EPSG 5044
 const pulkovo1942ToWgs84TransformationParams = {
     // translation in meters
     dx: 23.57,
     dy: -140.95,
     dz: -79.8,
     // rotation in arc-seconds
     rx: 0,
     ry: -0.35,
     rz: -0.79,
     // scale difference in parts per million
     ds: -0.22,
 };
 
 // Approximation according to note in EPSG 9607
 // const wgs84ToPulkovo1942TransformationParams = {
 //     dx: -pulkovo1942ToWgs84TransformationParams.dx,
 //     dy: -pulkovo1942ToWgs84TransformationParams.dy,
 //     dz: -pulkovo1942ToWgs84TransformationParams.dz,
 //     rx: -pulkovo1942ToWgs84TransformationParams.rx,
 //     ry: -pulkovo1942ToWgs84TransformationParams.ry,
 //     rz: -pulkovo1942ToWgs84TransformationParams.rz,
 //     ds: -pulkovo1942ToWgs84TransformationParams.ds,
 // };
 
 // EPSG 9602
 function geographic3DToGeocentric({lat, lon, h}, {a, inv_f}) {
     const degToRad = Math.PI / 180;
     const ϕ = lat * degToRad;
     const λ = lon * degToRad;
     const sin_ϕ = Math.sin(ϕ);
     const cos_ϕ = Math.cos(ϕ);
     const cos_λ = Math.cos(λ);
     const sin_λ = Math.sin(λ);
     const f = 1 / inv_f;
     const e_2 = 2 * f - f * f;
     const ν = a / Math.sqrt(1 - e_2 * sin_ϕ * sin_ϕ);
     return {
         x: (ν + h) * cos_ϕ * cos_λ,
         y: (ν + h) * cos_ϕ * sin_λ,
         z: ((1 - e_2) * ν + h) * sin_ϕ,
     };
 }
 
 // EPSG 9602
 function geocentricToGeographic3D({x, y, z}, {a, inv_f}) {
     const radToDeg = 180 / Math.PI;
     const f = 1 / inv_f;
     const b = a * (1 - f);
     const p = Math.sqrt(x * x + y * y);
     const q = Math.atan2(z * a, p * b);
     const sin_q_3 = Math.sin(q) ** 3;
     const cos_q_3 = Math.cos(q) ** 3;
     const e_2 = 2 * f - f * f;
     const ε = e_2 / (1 - e_2);
     const ϕ = Math.atan2(z + ε * b * sin_q_3, p - e_2 * a * cos_q_3);
     const λ = Math.atan2(y, x);
     const ν = a / Math.sqrt(1 - e_2 * Math.sin(ϕ) ** 2);
     const h = p / Math.cos(ϕ) - ν;
     return {
         lat: ϕ * radToDeg,
         lon: λ * radToDeg,
         h,
     };
 }
 
 /* eslint-enable camelcase */
 
 // EPSG 1032
 function rotateCoordinateFrameGeocentric({x, y, z}, params) {
     const arcSecToRad = Math.PI / 180 / 3600;
     const m = 1 + params.ds * 1e-6;
     const rx = params.rx * arcSecToRad;
     const ry = params.ry * arcSecToRad;
     const rz = params.rz * arcSecToRad;
     return {
         x: m * (x + y * rz - z * ry) + params.dx,
         y: m * (-x * rz + y + z * rx) + params.dy,
         z: m * (x * ry - y * rx + z) + params.dz,
     };
 }
 
 // EPSG 9659
 function geographic2DTo3D({lat, lon}) {
     return {lat, lon, h: 0};
 }
 
 // EPSG 9659
 // eslint-disable-next-line no-unused-vars
 function geographic3DTo2D({lat, lon, h}) {
     return {lat, lon};
 }
 
 // EPSG 9607
 function rotateCoordinateFrameGeog2D({lat, lon}, transformationParams, srcEllipsoid, targetEllipsoid) {
     const srcGeod3D = geographic2DTo3D({lat, lon});
     const srcGeocentric = geographic3DToGeocentric(srcGeod3D, srcEllipsoid);
     const destGeocentric = rotateCoordinateFrameGeocentric(srcGeocentric, transformationParams);
     const destGeog3D = geocentricToGeographic3D(destGeocentric, targetEllipsoid);
     return geographic3DTo2D(destGeog3D);
 }
 
 function pulkovo1942ToWgs84({lat, lon}) {
     return rotateCoordinateFrameGeog2D(
         {
             lat,
             lon,
         },
         pulkovo1942ToWgs84TransformationParams,
         ellipsoidKrassowsky1940,
         ellipsoidWGS1984
     );
 }
 
 // function wgs84ToPulkovo1942({lat, lon}) {
 //     return rotateCoordinateFrameGeog2D(
 //         {
 //             lat,
 //             lon,
 //         },
 //         wgs84ToPulkovo1942TransformationParams,
 //         ellipsoidWGS1984,
 //         ellipsoidKrassowsky1940
 //     );
 // }
 
 export {pulkovo1942ToWgs84};