Android – How to calculate moving average speed from GPS

androidgps

I'm developing an android application using GPS. I'd like to implement a feature that displays the users average speed over the 1/5/15 minute. Something like the CPU load on unix. I can calculate average easily by cumulating the distance traveled second by second and divide it by the elapsed time, but I can't think of a smart way of calculating the moving average.

Obviously I can get id done by putting the distance between the last and the current position in an array every second while deleting the oldest value.

I'm looking for a neat way of doing this.

Best Answer

Heres one way to go about it that is pretty straight forward:

If you are sampling position every second keep 901 samples in a queue, thats 15 mins worth (and 1 extra). Position 0 is the most recent measurement, effectively your current position.

For an average speed over the last X minutes:

s = X * 60;
point1 = postion_queue[0]; // this is your current position
point2 = postion_queue[s]; // this is your position s seconds ago
d = distance_between_points(point1, point2);
speed = d / s;

speed is now distance units per second, convert to mph, or kph or whatever units you need. Different values of X can be used for any average between 1 and 15 minutes.

Related Solutions

Android – How to get the current GPS location programmatically in Android

I have created a small application with step by step description to get current location's GPS coordinates.

Complete example source code is in Get Current Location coordinates , City name - in Android.

See how it works:

All we need to do is add this permission in the manifest file:

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

And create a LocationManager instance like this:

LocationManager locationManager = (LocationManager)
getSystemService(Context.LOCATION_SERVICE);

Check if GPS is enabled or not.

And then implement LocationListener and get coordinates:

LocationListener locationListener = new MyLocationListener();
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER, 5000, 10, locationListener);

Here is the sample code to do so

/*---------- Listener class to get coordinates ------------- */
private class MyLocationListener implements LocationListener {

    @Override
    public void onLocationChanged(Location loc) {
        editLocation.setText("");
        pb.setVisibility(View.INVISIBLE);
        Toast.makeText(
                getBaseContext(),
                "Location changed: Lat: " + loc.getLatitude() + " Lng: "
                    + loc.getLongitude(), Toast.LENGTH_SHORT).show();
        String longitude = "Longitude: " + loc.getLongitude();
        Log.v(TAG, longitude);
        String latitude = "Latitude: " + loc.getLatitude();
        Log.v(TAG, latitude);

        /*------- To get city name from coordinates -------- */
        String cityName = null;
        Geocoder gcd = new Geocoder(getBaseContext(), Locale.getDefault());
        List<Address> addresses;
        try {
            addresses = gcd.getFromLocation(loc.getLatitude(),
                    loc.getLongitude(), 1);
            if (addresses.size() > 0) {
                System.out.println(addresses.get(0).getLocality());
                cityName = addresses.get(0).getLocality();
            }
        }
        catch (IOException e) {
            e.printStackTrace();
        }
        String s = longitude + "\n" + latitude + "\n\nMy Current City is: "
            + cityName;
        editLocation.setText(s);
    }

    @Override
    public void onProviderDisabled(String provider) {}

    @Override
    public void onProviderEnabled(String provider) {}

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

Android – How to stop EditText from gaining focus at Activity startup in Android

Excellent answers from Luc and Mark. However, a good code sample is missing. Adding the tags android:focusableInTouchMode="true" and android:focusable="true" to the parent layout (e.g. LinearLayout or ConstraintLayout) like in the following example, will fix the problem.

<!-- Dummy item to prevent AutoCompleteTextView from receiving focus -->
<LinearLayout
    android:focusable="true" 
    android:focusableInTouchMode="true"
    android:layout_width="0px" 
    android:layout_height="0px"/>

<!-- :nextFocusUp and :nextFocusLeft have been set to the id of this component
to prevent the dummy from receiving focus again -->
<AutoCompleteTextView android:id="@+id/autotext"
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content"
    android:nextFocusUp="@id/autotext" 
    android:nextFocusLeft="@id/autotext"/>

Best Answer

Related Solutions

Android – How to get the current GPS location programmatically in Android

Android – How to stop EditText from gaining focus at Activity startup in Android

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