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How to get the coordinates of the buffer polygon (latitude and longitude) in iOS?

I created one polygon on the map with some set of coordinates. I need help creating one buffered polygon with some given distance outside the original border of the polygon.

so I need a method with such an algorithm in which I pass a coordinate set as input and should get a buffer coordinate set as output.

I tried to achieve this using the arcgis library for ios with the bufferGeometry AGSGeometryEngine method, but the problem is that it is closely related and will only work with their GIS Map, but I use Mapbox, which is a different Map. Therefore, I need one universal method that can solve my problem, independent for display.

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- . , . https://github.com/RanaRanvijaySingh/PolygonBuffer
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double distance = 0.0001;
List bufferedPolygonList = AreaBuffer.buffer(pointList, distance);

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  • LatLng. ( computeDistanceAndBearing (double lat1, double lon1, double lat2, double lon2) )

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  1. , , , LatLng ( computeDistanceAndBearing). ( , computeDestinationAndBearing ( double lat1, double lon1, double brng, double dist)). LatLng , .

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  1. , . , . ( computeIntersectionPoint (LatLng p1, double brng1, LatLng p2, double brng2)

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//computeDistanceAndBearing ( lat1, double lon1,                                                    double lat2, double lon2)

public static double[] computeDistanceAndBearing(double lat1, double lon1,
                                                 double lat2, double lon2) {
    // Based on http://www.ngs.noaa.gov/PUBS_LIB/inverse.pdf
    // using the "Inverse Formula" (section 4)
    double results[] = new double[3];
    int MAXITERS = 20;
    // Convert lat/long to radians
    lat1 *= Math.PI / 180.0;
    lat2 *= Math.PI / 180.0;
    lon1 *= Math.PI / 180.0;
    lon2 *= Math.PI / 180.0;

    double a = 6378137.0; // WGS84 major axis
    double b = 6356752.3142; // WGS84 semi-major axis
    double f = (a - b) / a;
    double aSqMinusBSqOverBSq = (a * a - b * b) / (b * b);

    double L = lon2 - lon1;
    double A = 0.0;
    double U1 = Math.atan((1.0 - f) * Math.tan(lat1));
    double U2 = Math.atan((1.0 - f) * Math.tan(lat2));

    double cosU1 = Math.cos(U1);
    double cosU2 = Math.cos(U2);
    double sinU1 = Math.sin(U1);
    double sinU2 = Math.sin(U2);
    double cosU1cosU2 = cosU1 * cosU2;
    double sinU1sinU2 = sinU1 * sinU2;

    double sigma = 0.0;
    double deltaSigma = 0.0;
    double cosSqAlpha = 0.0;
    double cos2SM = 0.0;
    double cosSigma = 0.0;
    double sinSigma = 0.0;
    double cosLambda = 0.0;
    double sinLambda = 0.0;

    double lambda = L; // initial guess
    for (int iter = 0; iter < MAXITERS; iter++) {
        double lambdaOrig = lambda;
        cosLambda = Math.cos(lambda);
        sinLambda = Math.sin(lambda);
        double t1 = cosU2 * sinLambda;
        double t2 = cosU1 * sinU2 - sinU1 * cosU2 * cosLambda;
        double sinSqSigma = t1 * t1 + t2 * t2; // (14)
        sinSigma = Math.sqrt(sinSqSigma);
        cosSigma = sinU1sinU2 + cosU1cosU2 * cosLambda; // (15)
        sigma = Math.atan2(sinSigma, cosSigma); // (16)
        double sinAlpha = (sinSigma == 0) ? 0.0 : cosU1cosU2 * sinLambda
                / sinSigma; // (17)
        cosSqAlpha = 1.0 - sinAlpha * sinAlpha;
        cos2SM = (cosSqAlpha == 0) ? 0.0 : cosSigma - 2.0 * sinU1sinU2
                / cosSqAlpha; // (18)

        double uSquared = cosSqAlpha * aSqMinusBSqOverBSq; // defn
        A = 1 + (uSquared / 16384.0) * // (3)
                (4096.0 + uSquared * (-768 + uSquared * (320.0 - 175.0 * uSquared)));
        double B = (uSquared / 1024.0) * // (4)
                (256.0 + uSquared * (-128.0 + uSquared * (74.0 - 47.0 * uSquared)));
        double C = (f / 16.0) * cosSqAlpha * (4.0 + f * (4.0 - 3.0 * cosSqAlpha)); // (10)
        double cos2SMSq = cos2SM * cos2SM;
        deltaSigma = B
                * sinSigma
                * // (6)
                (cos2SM + (B / 4.0)
                        * (cosSigma * (-1.0 + 2.0 * cos2SMSq) - (B / 6.0) * cos2SM
                        * (-3.0 + 4.0 * sinSigma * sinSigma)
                        * (-3.0 + 4.0 * cos2SMSq)));

        lambda = L
                + (1.0 - C)
                * f
                * sinAlpha
                * (sigma + C * sinSigma
                * (cos2SM + C * cosSigma * (-1.0 + 2.0 * cos2SM * cos2SM))); // (11)

        double delta = (lambda - lambdaOrig) / lambda;
        if (Math.abs(delta) < 1.0e-12) {
            break;
        }
    }

    double distance = (b * A * (sigma - deltaSigma));
    results[0] = distance;
    if (results.length > 1) {
        double initialBearing = Math.atan2(cosU2 * sinLambda, cosU1 * sinU2
                - sinU1 * cosU2 * cosLambda);
        initialBearing *= 180.0 / Math.PI;
        results[1] = initialBearing;
        if (results.length > 2) {
            double finalBearing = Math.atan2(cosU1 * sinLambda, -sinU1 * cosU2
                    + cosU1 * sinU2 * cosLambda);
            finalBearing *= 180.0 / Math.PI;
            results[2] = finalBearing;
        }
    }

    return results;
}

//computeDestinationAndBearing (double lat1, double lon1, double brng, double dist)

public static double[] computeDestinationAndBearing(double lat1, double lon1,
                                                    double brng, double dist) {
    double results[] = new double[3];
    double a = 6378137, b = 6356752.3142, f = 1 / 298.257223563; // WGS-84
    // ellipsiod
    double s = dist;
    double alpha1 = toRad(brng);
    double sinAlpha1 = Math.sin(alpha1);
    double cosAlpha1 = Math.cos(alpha1);

    double tanU1 = (1 - f) * Math.tan(toRad(lat1));
    double cosU1 = 1 / Math.sqrt((1 + tanU1 * tanU1)), sinU1 = tanU1 * cosU1;
    double sigma1 = Math.atan2(tanU1, cosAlpha1);
    double sinAlpha = cosU1 * sinAlpha1;
    double cosSqAlpha = 1 - sinAlpha * sinAlpha;
    double uSq = cosSqAlpha * (a * a - b * b) / (b * b);
    double A = 1 + uSq / 16384
            * (4096 + uSq * (-768 + uSq * (320 - 175 * uSq)));
    double B = uSq / 1024 * (256 + uSq * (-128 + uSq * (74 - 47 * uSq)));
    double sinSigma = 0, cosSigma = 0, deltaSigma = 0, cos2SigmaM = 0;
    double sigma = s / (b * A), sigmaP = 2 * Math.PI;

    while (Math.abs(sigma - sigmaP) > 1e-12) {
        cos2SigmaM = Math.cos(2 * sigma1 + sigma);
        sinSigma = Math.sin(sigma);
        cosSigma = Math.cos(sigma);
        deltaSigma = B
                * sinSigma
                * (cos2SigmaM + B
                / 4
                * (cosSigma * (-1 + 2 * cos2SigmaM * cos2SigmaM) - B / 6
                * cos2SigmaM * (-3 + 4 * sinSigma * sinSigma)
                * (-3 + 4 * cos2SigmaM * cos2SigmaM)));
        sigmaP = sigma;
        sigma = s / (b * A) + deltaSigma;
    }

    double tmp = sinU1 * sinSigma - cosU1 * cosSigma * cosAlpha1;
    double lat2 = Math.atan2(sinU1 * cosSigma + cosU1 * sinSigma * cosAlpha1,
            (1 - f) * Math.sqrt(sinAlpha * sinAlpha + tmp * tmp));
    double lambda = Math.atan2(sinSigma * sinAlpha1, cosU1 * cosSigma - sinU1
            * sinSigma * cosAlpha1);
    double C = f / 16 * cosSqAlpha * (4 + f * (4 - 3 * cosSqAlpha));
    double L = lambda
            - (1 - C)
            * f
            * sinAlpha
            * (sigma + C * sinSigma
            * (cos2SigmaM + C * cosSigma * (-1 + 2 * cos2SigmaM * cos2SigmaM)));
    double lon2 = (toRad(lon1) + L + 3 * Math.PI) % (2 * Math.PI) - Math.PI; // normalise
    // to
    // -180...+180

    double revAz = Math.atan2(sinAlpha, -tmp); // final bearing, if required

    results[0] = toDegrees(lat2);
    results[1] = toDegrees(lon2);
    results[2] = toDegrees(revAz);
    return results;
}

private static double toRad(double angle) {
    return angle * Math.PI / 180;
}

private static double toDegrees(double radians) {
    return radians * 180 / Math.PI;
}

//computeIntersectionPoint (LatLng p1, double brng1, LatLng p2, double brng2)

    public static LatLng computeIntersectionPoint(LatLng p1, double brng1, LatLng p2, double brng2) {
    double lat1 = toRad(p1.latitude), lng1 = toRad(p1.longitude);
    double lat2 = toRad(p2.latitude), lng2 = toRad(p2.longitude);
    double brng13 = toRad(brng1), brng23 = toRad(brng2);
    double dlat = lat2 - lat1, dlng = lng2 - lng1;
    double delta12 = 2 * Math.asin(Math.sqrt(Math.sin(dlat / 2) * Math.sin(dlat / 2)
            + Math.cos(lat1) * Math.cos(lat2) * Math.sin(dlng / 2) * Math.sin(dlng / 2)));

    if (delta12 == 0) return null;


    double initBrng1 = Math.acos((Math.sin(lat2) - Math.sin(lat1) * Math.cos(delta12)) / (Math.sin(delta12) * Math.cos(lat1)));

    double initBrng2 = Math.acos((Math.sin(lat1) - Math.sin(lat2) * Math.cos(delta12)) / (Math.sin(delta12) * Math.cos(lat2)));

    double brng12 = Math.sin(lng2 - lng1) > 0 ? initBrng1 : 2 * Math.PI - initBrng1;
    double brng21 = Math.sin(lng2 - lng1) > 0 ? 2 * Math.PI - initBrng2 : initBrng2;


    double alpha1 = (brng13 - brng12 + Math.PI) % (2 * Math.PI) - Math.PI; 
    double alpha2 = (brng21 - brng23 + Math.PI) % (2 * Math.PI) - Math.PI; 

    double alpha3 = Math.acos(-Math.cos(alpha1) * Math.cos(alpha2) + Math.sin(alpha1) * Math.sin(alpha2) * Math.cos(delta12));
    double delta13 = Math.atan2(Math.sin(delta12) * Math.sin(alpha1) * Math.sin(alpha2), Math.cos(alpha2) + Math.cos(alpha1) * Math.cos(alpha3));
    double lat3 = Math.asin(Math.sin(lat1) * Math.cos(delta13) + Math.cos(lat1) * Math.sin(delta13) * Math.cos(brng13));
    double dlng13 = Math.atan2(Math.sin(brng13) * Math.sin(delta13) * Math.cos(lat1), Math.cos(delta13) - Math.sin(lat1) * Math.sin(lat3));
    double lng3 = lng1 + dlng13;

    return new LatLng(toDegrees(lat3), (toDegrees(lng3) + 540) % 360 - 180); 
}

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, , , ios, , , javascript.

!!!

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computeDistanceAndBearing. , 3 : 1 2 . 1. , computeDestinationAndBearing. 2. computeIntersectionPoint, .

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computeDistanceAndBearing. , 3 : 1 2 . 1. , computeDestinationAndBearing. 2. computeIntersectionPoint, .

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BOOST, ++, / , , , , .

Boost, , , 1.58.0, BOOST/Geometry/Strategies/Cartesian/buffer [Something] -Square/Miter/Round

(lat/long) (x/y) Boost . ArcGIS .

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Turf.js gis. . , MapBox.js .
: Turf.js Buffer

, . API- Arcgis Javascript API

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