Question

我希望得到两个纬度和经度之间的距离，单位为米/公里。所以我使用以下功能。它给了我与谷歌地图不同的结果。

你能帮我解决我的问题吗？我不明白这是什么问题？

代码

   float[] results = {0};

   android.location.Location.distanceBetween(lat1, lon1, lat2, lon2, results);

当前纬度= 23.012281666666663 当前经度= 72.51798333333333

目标纬度= 23.1120487 目标纬度= 72.5766759

它在Meter中得出此结果= 12579.679，而在谷歌地图中，它给出的结果= 17.9 Km

我不明白为什么这两个会给出不同的结果。

Answer 1

此图解释了为什么你得到12.5和17.6公里

enter image description here

要计算行驶距离（17.6 km），您需要使用directions API

Answer 2

您可以使用此 2功能来查找距离

* 注意： *如果你无法正确获得距离，那么尝试将MILLION var设置为1，因为在我的情况下，我将lat-long值乘以1E6，因此必须除以它。

public double calcdist() {
            int MILLION = 1000000;
            int EARTH_RADIUS_KM = 6371;

            double lat1 = la1 / MILLION;
            double lon1 = lo1 / MILLION;
            double lat2 = la2 / MILLION;
            double lon2 = lo2 / MILLION;

            double lat1Rad = Math.toRadians(lat1);
            double lat2Rad = Math.toRadians(lat2);
            double deltaLonRad = Math.toRadians(lon2 - lon1);

            double dist = Math
                    .acos(Math.sin(lat1Rad) * Math.sin(lat2Rad) + Math.cos(lat1Rad)
                            * Math.cos(lat2Rad) * Math.cos(deltaLonRad))
                    * EARTH_RADIUS_KM;
            return dist;

        }

和

private float round(float dist, int i) {
        float p1 = (float) Math.pow(10, i);
        dist = dist * p1;
        float tmp = Math.round(dist);
        return (float) tmp / p1;
    }

然后将它们用作

float tempdist = (float) calcdist();
dist = round(tempdist, 2);

Answer 3

嘿，我在这里找到了一个源代码，而人们说它会返回正确的公路距离。我没试过，但你可以尝试告诉我它是否真的有效。的 GPSSample.java

我不知道你是如何传递Lat - Long值的。请尝试一下这整个示例代码。

并在android.location.Location.java中为此编写的代码如下所示..如果您希望可以直接在您的应用中使用此代码。

private static void computeDistanceAndBearing(double lat1, double lon1, double lat2, double lon2, float[] results) { // Based on http://www.ngs.noaa.gov/PUBS_LIB/inverse.pdf // using the "Inverse Formula" (section 4) 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; } } float distance = (float) (b * A * (sigma - deltaSigma)); results[0] = distance; if (results.length > 1) { float initialBearing = (float) Math.atan2( cosU2 * sinLambda, cosU1 * sinU2 - sinU1 * cosU2 * cosLambda); initialBearing *= 180.0 / Math.PI; results[1] = initialBearing; if (results.length > 2) { float finalBearing = (float) Math.atan2(cosU1 * sinLambda, -sinU1 * cosU2 + cosU1 * sinU2 * cosLambda); finalBearing *= 180.0 / Math.PI; results[2] = finalBearing; } } }

使用Google Map和用户定义函数时获得不同的距离

3 个答案: