2014-11-05 94 views
-1

我对Java很新颖& Android和我有一些代码问题。Android GPS精确距离测量

location1.distanceTo(location2)方法是否也考虑海拔变化计算距离?

另一个问题是,尽管我没有移动设备,但测得的距离发生了变化。 这是我的代码:

public class GpsCalculator{ 
public Activity activity; 
private LocationManager locationManager = null; 
private Location previousLocation = null; 
private double totalDistance = 0D; 
private Context context; 
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 1; // 1 meter 
private static final long MIN_TIME_BW_UPDATES = 1000; // 1 second 
TextView distance_tracker; 

public GpsCalculator(TextView dt) { 
    distance_tracker = dt; 
} 


public void run(Context act){ 
    context = act; 
    // Get the location manager 
    locationManager = (LocationManager) context.getSystemService(Service.LOCATION_SERVICE); 

    // Add new listeners with the given params 
    locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, MIN_TIME_BW_UPDATES, MIN_DISTANCE_CHANGE_FOR_UPDATES, locationListener); // Network location 
    locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, MIN_TIME_BW_UPDATES, MIN_DISTANCE_CHANGE_FOR_UPDATES, locationListener); // Gps location 
} 

public void stop(){ 
    locationManager.removeUpdates(locationListener); 
} 
DecimalFormat df = new DecimalFormat("#"); 
private LocationListener locationListener = new LocationListener(){ 
    @Override 
    public void onLocationChanged(Location newLocation){ 
     if (previousLocation != null){ 
      GpsCalculator.this.totalDistance += previousLocation.distanceTo(newLocation); 
     } 

     // Update stored location 
     GpsCalculator.this.previousLocation = newLocation; 

     CharSequence text = Double.toString(totalDistance); 
     int duration = Toast.LENGTH_SHORT; 

     Toast toast = Toast.makeText(context, text, duration); 
     toast.show(); 

     distance_tracker.setText(df.format(totalDistance)+ " m"); 
    } 

    @Override 
    public void onProviderDisabled(String provider) {} 

    @Override 
    public void onProviderEnabled(String provider) {} 

    @Override 
    public void onStatusChanged(String provider, int status, Bundle extras) {} 
}; } 

我想提一提的是,精度问题坚持用或不用网络提供商监听。

结论

的代码是正确的,但GPS数据的准确性是没有的。我从Carsten的回答下的评论中理解了这一点。

回答

1

位置对象通常还包含高度信息,因此要考虑高程。

更新之间的位置是否更改?我会这样认为,因为它在你的案例中每秒更新一次。

+0

那么,我该如何优化代码,如果我不动,距离不会改变? – 2014-11-05 12:36:22

+0

我会坚持GPS提供商,增加MIN_DISTANCE_CHANGE_FOR_UPDATES并增加MIN_TIME_BW_UPDATES。由于您可能也会从其他来源获取更新,因此如果上次更新与新版本之间的距离足够满足您的用途,则也值得验证自己。 – Carsten 2014-11-05 12:47:10

+0

感谢您提醒我GPS卫星的精度不是1米。我正在做户外活动,所以我想我会骑自行车并骑一下:) – 2014-11-05 13:02:13