计算android中两个经纬度点之间的距离

Question

我怎样才能找到two latitude&longitudepoints 之间的距离

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对于其中一个纬度和经度点,我在数据库和另一个我想使用移动设备的当前位置

我需要在下面使用哪一个:

• android位置提供者
• Google API
• 数学计算

note ::任何演示代码示例都很有用

Answer 1

您可以使用内置算法:

Location locationA = new Location("point A");     
locationA.setLatitude(latA); 
locationA.setLongitude(lngA);
Location locationB = new Location("point B");
locationB.setLatitude(latB); 
LocationB.setLongitude(lngB);
distance = locationA.distanceTo(locationB) ;

更新:(我没有任何错误)

LatLng latLngA = new LatLng(12.3456789,98.7654321);
LatLng latLngB = new LatLng(98.7654321,12.3456789);

Location locationA = new Location("point A");
locationA.setLatitude(latLngA.latitude);
locationA.setLongitude(latLngA.longitude);
Location locationB = new Location("point B");
locationB.setLatitude(latLngB.latitude);
locationB.setLongitude(latLngB.longitude);

double distance = locationA.distanceTo(locationB);

Answer 2

您可以使用Haversine算法.另一位用户已经为此编写了一个解决方案:

public double CalculationByDistance(double initialLat, double initialLong,
                            double finalLat, double finalLong){
int R = 6371; // km
double dLat = toRadians(finalLat-initialLat);
double dLon = toRadians(finalLong-initialLong);
lat1 = toRadians(lat1);
lat2 = toRadians(lat2);

double a = Math.sin(dLat/2) * Math.sin(dLat/2) +
        Math.sin(dLon/2) * Math.sin(dLon/2) * Math.cos(lat1) * Math.cos(lat2); 
double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a)); 
return R * c;
}

public double toRadians(deg) {
  return deg * (Math.PI/180)
}

资料来源:https://stackoverflow.com/a/17787472/3449528