通用逻辑寻找朝拜方向 [英] Universal Logic for finding qibla direction
问题描述
我非常想知道一个通用的qibla方向逻辑,因为我想在我的伊斯兰android应用程序中实现它.我刚刚获得了用户的经度和纬度,并且无论该人身在英国,美国,印度,斯里兰卡还是任何地方,我都想找到该人的朝拜方向.
I am very keen on knowing an universal qibla direction logic as I want to implement in my islamic android app. I have just obtained latitude and longitude of the user and irrespective of any lat, lon I want to find qibla direction for that person whether the person is in UK, US, India, Sri Lanka or any where.
我找到了这个公式,但不知道它是如何工作的:
I found this formula, and don't know how exactly it works:
float lonDelta = (lon2 - lon1);
float y = Math.sin(lonDelta) * Math.cos(lat2);
float x = Math.cos(lat1) * Math.sin(lat2) - Math.sin(lat1) * Math.cos(lat2) * Math.cos(lonDelta);
float brng = Math.atan2(y, x).toDeg();
请帮助我了解确切的公式.
Please help me in knowing exact formula.
推荐答案
代替使用此公式
float lonDelta = (lon2 - lon1);
float y = Math.sin(lonDelta) * Math.cos(lat2);
float x = Math.cos(lat1) * Math.sin(lat2) - Math.sin(lat1) * Math.cos(lat2) * Math.cos(lonDelta);
float brng = Math.atan2(y, x).toDeg();
您可以通过这种方式简单地使用bearingTo
you can simple use bearingTo in this way
Location userLoc=new Location("service Provider");
//get longitudeM Latitude and altitude of current location with gps class and set in userLoc
userLoc.setLongitude(longitude);
userLoc.setLatitude(latitude);
userLoc.setAltitude(altitude);
Location destinationLoc = new Location("service Provider");
destinationLoc.setLatitude(21.422487); //kaaba latitude setting
destinationLoc.setLongitude(39.826206); //kaaba longitude setting
float bearTo=userLoc.bearingTo(destinationLoc);
bearingTo将为您提供-180至180的范围,这会使您感到有些困惑.我们需要将此值转换为0到360之间的一个范围,以获取正确的旋转角度.
bearingTo will give you a range from -180 to 180, which will confuse things a bit. We will need to convert this value into a range from 0 to 360 to get the correct rotation.
这是一张我们真正想要的表,与bearingTo给我们的结果相比
This is a table of what we really want, comparing to what bearingTo gives us
+-----------+--------------+
| bearingTo | Real bearing |
+-----------+--------------+
| 0 | 0 |
+-----------+--------------+
| 90 | 90 |
+-----------+--------------+
| 180 | 180 |
+-----------+--------------+
| -90 | 270 |
+-----------+--------------+
| -135 | 225 |
+-----------+--------------+
| -180 | 180 |
+-----------+--------------+
所以我们必须在bearTo之后添加此代码
so we have to add this code after bearTo
// If the bearTo is smaller than 0, add 360 to get the rotation clockwise.
if (bearTo < 0) {
bearTo = bearTo + 360;
//bearTo = -100 + 360 = 260;
}
您需要实现SensorEventListener及其功能(onSensorChanged,onAcurracyChabge)并在onSensorChanged内编写所有代码
you need to implements the SensorEventListener and its functions(onSensorChanged,onAcurracyChabge) and write all the code inside onSensorChanged
完整的代码位于朝拜罗盘的方向
public class QiblaDirectionCompass extends Service implements SensorEventListener{
public static ImageView image,arrow;
// record the compass picture angle turned
private float currentDegree = 0f;
private float currentDegreeNeedle = 0f;
Context context;
Location userLoc=new Location("service Provider");
// device sensor manager
private static SensorManager mSensorManager ;
private Sensor sensor;
public static TextView tvHeading;
public QiblaDirectionCompass(Context context, ImageView compass, ImageView needle,TextView heading, double longi,double lati,double alti ) {
image = compass;
arrow = needle;
// TextView that will tell the user what degree is he heading
tvHeading = heading;
userLoc.setLongitude(longi);
userLoc.setLatitude(lati);
userLoc.setAltitude(alti);
mSensorManager = (SensorManager) context.getSystemService(SENSOR_SERVICE);
sensor = mSensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION);
if(sensor!=null) {
// for the system's orientation sensor registered listeners
mSensorManager.registerListener(this, sensor, SensorManager.SENSOR_DELAY_GAME);//SensorManager.SENSOR_DELAY_Fastest
}else{
Toast.makeText(context,"Not Supported", Toast.LENGTH_SHORT).show();
}
// initialize your android device sensor capabilities
this.context =context;
@Override
public void onCreate() {
// TODO Auto-generated method stub
Toast.makeText(context, "Started", Toast.LENGTH_SHORT).show();
mSensorManager.registerListener(this, sensor, SensorManager.SENSOR_DELAY_GAME); //SensorManager.SENSOR_DELAY_Fastest
super.onCreate();
}
@Override
public void onDestroy() {
mSensorManager.unregisterListener(this);
Toast.makeText(context, "Destroy", Toast.LENGTH_SHORT).show();
super.onDestroy();
}
@Override
public void onSensorChanged(SensorEvent sensorEvent) {
float degree = Math.round(sensorEvent.values[0]);
float head = Math.round(sensorEvent.values[0]);
float bearTo;
Location destinationLoc = new Location("service Provider");
destinationLoc.setLatitude(21.422487); //kaaba latitude setting
destinationLoc.setLongitude(39.826206); //kaaba longitude setting
float bearTo=userLoc.bearingTo(destinationLoc);
//bearTo = The angle from true north to the destination location from the point we're your currently standing.(asal image k N se destination taak angle )
//head = The angle that you've rotated your phone from true north. (jaise image lagi hai wo true north per hai ab phone jitne rotate yani jitna image ka n change hai us ka angle hai ye)
GeomagneticField geoField = new GeomagneticField( Double.valueOf( userLoc.getLatitude() ).floatValue(), Double
.valueOf( userLoc.getLongitude() ).floatValue(),
Double.valueOf( userLoc.getAltitude() ).floatValue(),
System.currentTimeMillis() );
head -= geoField.getDeclination(); // converts magnetic north into true north
if (bearTo < 0) {
bearTo = bearTo + 360;
//bearTo = -100 + 360 = 260;
}
//This is where we choose to point it
float direction = bearTo - head;
// If the direction is smaller than 0, add 360 to get the rotation clockwise.
if (direction < 0) {
direction = direction + 360;
}
tvHeading.setText("Heading: " + Float.toString(degree) + " degrees" );
RotateAnimation raQibla = new RotateAnimation(currentDegreeNeedle, direction, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
raQibla.setDuration(210);
raQibla.setFillAfter(true);
arrow.startAnimation(raQibla);
currentDegreeNeedle = direction;
// create a rotation animation (reverse turn degree degrees)
RotateAnimation ra = new RotateAnimation(currentDegree, -degree, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
// how long the animation will take place
ra.setDuration(210);
// set the animation after the end of the reservation status
ra.setFillAfter(true);
// Start the animation
image.startAnimation(ra);
currentDegree = -degree;
}
@Override
public void onAccuracyChanged(Sensor sensor, int i) {
}
@Nullable
@Override
public IBinder onBind(Intent intent) {
return null;
}
xml代码在这里
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/flag_pakistan">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/heading"
android:textColor="@color/colorAccent"
android:layout_centerHorizontal="true"
android:layout_marginBottom="100dp"
android:layout_marginTop="20dp"
android:text="Heading: 0.0" />
<RelativeLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/heading"
android:scaleType="centerInside"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true">
<ImageView
android:id="@+id/imageCompass"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="centerInside"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true"
android:src="@drawable/images_compass"/>
<ImageView
android:id="@+id/needle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true"
android:scaleType="centerInside"
android:src="@drawable/arrow2"/>
</RelativeLayout>
</RelativeLayout>
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