Check if a latitude and longitude is within a circle

See this illustration:

What I would like to know is:

How to create an area (circle) when given a latitude and longitude and the distance (10 kilometers)

How to check (calculate) if a latitude and longitude is either inside or outside the area

I would prefer if you can give me code example in Java or specifically for Android with Google Maps API V2

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What you basically need, is the distance between to points on the map:

float[] results = new float[1];
Location.distanceBetween(centerLatitude, centerLongitude, testLatitude, testLongitude, results);
float distanceInMeters = results[0];
boolean isWithin10km = distanceInMeters < 10000;

If you have already Location objects:

Location center;
Location test;
float distanceInMeters = center.distanceTo(test);
boolean isWithin10km = distanceInMeters < 10000;

Here is the interesting part of that API: https://developer.android.com/reference/android/location/Location.html

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Have you gone through the new GeoFencing API. It should help you. Normal implementation takes a lot of time. This should help you implementing it easily.

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请参阅https://developer.android.com/reference/android/location/Location.html

Location areaOfIinterest = new Location;
Location currentPosition = new Location;

areaOfIinterest.setLatitude(aoiLat);
areaOfIinterest.setLongitude(aoiLong);

currentPosition.setLatitude(myLat);
currentPosition.setLongitude(myLong);

float dist = areaOfIinterest.distanceTo(currentPosition);

return (dist < 10000);

链接地址: http://www.djcxy.com/p/84906.html

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