[我尝试在android studio中计算Google地图中两点之间的距离，其值与原始Google地图中的值不同

Question

[我尝试在android studio中计算Google地图中两点之间的距离，并且值与原始Google地图不同。结果差异很大。

从港口到马德里，结果范围超过100公里...

这是我的代码：

                                double lat1 = toRadians(latposto);
                                double lat2 = toRadians(myLocationLat);
                                double long1 = toRadians(longposto);
                                double long2 = toRadians(myLocationLong);

                                double dist = acos(sin(lat1) * sin(lat2) + cos(lat1) * cos(lat2) * cos(long1 - long2));
                                if(dist < 0) {
                                    dist = dist + Math.PI;
                                }
                                double distancia = Math.round(dist * 6378100) * 0.001;
                                String distanciakm = String.format("%.2f", distancia);
                                km.setText(String.valueOf(distanciakm) + " km");

I have tried this way too and the result is the same ...:
                        double distance;
                        Location locationA = new Location("");
                        locationA.setLatitude(address.getLatitude());
                        locationA.setLongitude(address.getLongitude());
                        Location locationB = new Location("");
                        locationB.setLatitude(myLocationLat);
                        locationB.setLongitude(myLocationLong);
                        distance = locationA.distanceTo(locationB)/1000;
                       // kmeter.setText(String.valueOf(distance));

Answer 1

如果距离较长，结果可能会有所不同，您使用的是球形地球模型，我猜想distanceTo方法是基于像Vincenty公式这样的更精确的值。