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javaandroidgoogle-maps-android-api-2latitude-longitudearea

Check if a latitude and longitude is within a circle

See this illustration:

enter image description here

What I would like to know is:

  1. How to create an area (circle) when given a latitude and longitude and the distance (10 kilometers)
  2. 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

Solution

  • What you basically need, is the distance between two 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 the API used: https://developer.android.com/reference/android/location/Location.html