Comparing two locations for accuracy in Android

If you are developing a android application which uses android Location Service and you need to find best estimated location by comparing two locations, where one location is the currently obtained location and other is from the location fix then this post contains answer to your question. The below mentioned code contains a method isBetterLocation which will compare two locations and will return true if current location is more accurate than location fix. You might expect that the most recent location fix is the most accurate. However, because the accuracy of a location fix varies, the most recent fix is not always the best.

isBetterLocation method follows following criteria for choosing location fixes, you vary this criteria depending on the use-cases of the application and field testing.

  • Check if the location retrieved is significantly newer than the previous estimate.
  • Check if the accuracy claimed by the location is better or worse than the previous estimate.
  • Check which provider the new location is from and determine if you trust it more.
private static final int TWO_MINUTES = 1000 * 60 * 2;/** Determines whether one Location reading is better than the current Location fix  * @param location  The new Location that you want to evaluate  * @param currentBestLocation  The current Location fix, to which you want to compare the new one  */protected boolean isBetterLocation(Location location, Location currentBestLocation) {    if (currentBestLocation == null) {        // A new location is always better than no location        return true;    }    // Check whether the new location fix is newer or older    long timeDelta = location.getTime() - currentBestLocation.getTime();    boolean isSignificantlyNewer = timeDelta > TWO_MINUTES;    boolean isSignificantlyOlder = timeDelta < -TWO_MINUTES;    boolean isNewer = timeDelta > 0;    // If it's been more than two minutes since the current location, use the new location    // because the user has likely moved    if (isSignificantlyNewer) {        return true;    // If the new location is more than two minutes older, it must be worse    } else if (isSignificantlyOlder) {        return false;    }    // Check whether the new location fix is more or less accurate    int accuracyDelta = (int) (location.getAccuracy() - currentBestLocation.getAccuracy());    boolean isLessAccurate = accuracyDelta > 0;    boolean isMoreAccurate = accuracyDelta < 0;    boolean isSignificantlyLessAccurate = accuracyDelta > 200;    // Check if the old and new location are from the same provider    boolean isFromSameProvider = isSameProvider(location.getProvider(),            currentBestLocation.getProvider());    // Determine location quality using a combination of timeliness and accuracy    if (isMoreAccurate) {        return true;    } else if (isNewer && !isLessAccurate) {        return true;    } else if (isNewer && !isSignificantlyLessAccurate && isFromSameProvider) {        return true;    }    return false;}/** Checks whether two providers are the same */private boolean isSameProvider(String provider1, String provider2) {    if (provider1 == null) {      return provider2 == null;    }    return provider1.equals(provider2);}


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