Best Way to Get Geo-Location in Java

How can I get the current geographical location in my desktop application?

If this is a desktop application, then you only have 2 options. Either

• the desktop computer you're on has a GPS capability (e.g. a USB GPS receiver) which is highly unlikely
• or you will need to rely on the user's IP

If you want to do the latter, then in Java you can easily figure out the user's IP and then you'll need to use geo-IP services e.g. Maxmind. Have a look at their demo here.

What is the simplest and most robust way to get the user's current location on Android?

Here's what I do:

1. First of all I check what providers are enabled. Some may be disabled on the device, some may be disabled in application manifest.
2. If any provider is available I start location listeners and timeout timer. It's 20 seconds in my example, may not be enough for GPS so you can enlarge it.
3. If I get update from location listener I use the provided value. I stop listeners and timer.
4. If I don't get any updates and timer elapses I have to use last known values.
5. I grab last known values from available providers and choose the most recent of them.

Here's how I use my class:

LocationResult locationResult = new LocationResult(){
    @Override
    public void gotLocation(Location location){
        //Got the location!
    }
};
MyLocation myLocation = new MyLocation();
myLocation.getLocation(this, locationResult);

And here's MyLocation class:

import java.util.Timer;
import java.util.TimerTask;
import android.content.Context;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;

public class MyLocation {
    Timer timer1;
    LocationManager lm;
    LocationResult locationResult;
    boolean gps_enabled=false;
    boolean network_enabled=false;

    public boolean getLocation(Context context, LocationResult result)
    {
        //I use LocationResult callback class to pass location value from MyLocation to user code.
        locationResult=result;
        if(lm==null)
            lm = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);

        //exceptions will be thrown if provider is not permitted.
        try{gps_enabled=lm.isProviderEnabled(LocationManager.GPS_PROVIDER);}catch(Exception ex){}
        try{network_enabled=lm.isProviderEnabled(LocationManager.NETWORK_PROVIDER);}catch(Exception ex){}

        //don't start listeners if no provider is enabled
        if(!gps_enabled && !network_enabled)
            return false;

        if(gps_enabled)
            lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListenerGps);
        if(network_enabled)
            lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListenerNetwork);
        timer1=new Timer();
        timer1.schedule(new GetLastLocation(), 20000);
        return true;
    }

    LocationListener locationListenerGps = new LocationListener() {
        public void onLocationChanged(Location location) {
            timer1.cancel();
            locationResult.gotLocation(location);
            lm.removeUpdates(this);
            lm.removeUpdates(locationListenerNetwork);
        }
        public void onProviderDisabled(String provider) {}
        public void onProviderEnabled(String provider) {}
        public void onStatusChanged(String provider, int status, Bundle extras) {}
    };

    LocationListener locationListenerNetwork = new LocationListener() {
        public void onLocationChanged(Location location) {
            timer1.cancel();
            locationResult.gotLocation(location);
            lm.removeUpdates(this);
            lm.removeUpdates(locationListenerGps);
        }
        public void onProviderDisabled(String provider) {}
        public void onProviderEnabled(String provider) {}
        public void onStatusChanged(String provider, int status, Bundle extras) {}
    };

    class GetLastLocation extends TimerTask {
        @Override
        public void run() {
             lm.removeUpdates(locationListenerGps);
             lm.removeUpdates(locationListenerNetwork);

             Location net_loc=null, gps_loc=null;
             if(gps_enabled)
                 gps_loc=lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
             if(network_enabled)
                 net_loc=lm.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);

             //if there are both values use the latest one
             if(gps_loc!=null && net_loc!=null){
                 if(gps_loc.getTime()>net_loc.getTime())
                     locationResult.gotLocation(gps_loc);
                 else
                     locationResult.gotLocation(net_loc);
                 return;
             }

             if(gps_loc!=null){
                 locationResult.gotLocation(gps_loc);
                 return;
             }
             if(net_loc!=null){
                 locationResult.gotLocation(net_loc);
                 return;
             }
             locationResult.gotLocation(null);
        }
    }

    public static abstract class LocationResult{
        public abstract void gotLocation(Location location);
    }
}

Somebody may also want to modify my logic. For example if you get update from Network provider don't stop listeners but continue waiting. GPS gives more accurate data so it's worth waiting for it. If timer elapses and you've got update from Network but not from GPS then you can use value provided from Network.

One more approach is to use LocationClient http://developer.android.com/training/location/retrieve-current.html. But it requires Google Play Services apk to be installed on user device.

Get user's current latitude and longitude in Java

Java doesn't currently provide a general platform-independent API to get location. However, there may be platform-specific ways.

Most implementations on a desktop machine will geolocate via IP address; you can use these services from Java (Best way to get geo-location in Java). However, if operating systems provide a more general API, it can take advantage of any GPS hardware.

For Mac OS, https://superuser.com/questions/346302/is-there-a-way-to-access-os-x-location-services-from-the-command-line

There's detail here of a Gnome-provided library, and also a write-up of plans for support in KDE.

Java library to get geo-code from ipaddress

http://www.maxmind.com/app/developers provides a local database and java classes to calculate the location information from IP address. I did some testing. The results seem to be good.

bbc.co.uk: 212.58.241.131 : 51.283295,-0.23330688;Tadworth,N7,United Kingdom,null
home: 76.126.242.196 : 37.369705,-122.0214;Sunnyvale,CA,United States,94086
google.com: 74.125.224.133 : 37.419205,-122.0574;Mountain View,CA,United States,94043
tcs.in: 202.71.129.225 : 28.666702,77.216705;Delhi,07,India,null
ebay.com: 66.135.205.13 : 37.280304,-121.956696;Campbell,CA,United States,95008
etrade.com: 12.153.224.22 : 34.091797,-84.2209;Alpharetta,GA,United States,30005
whitehouse.gov: 72.247.136.110 : 42.362595,-71.0843;Cambridge,MA,United States,02142

Here is the link to the junit testcase I used, GeoLiteCityTest.java

MaxMind provides java classes, but not jars. So, I have created a maven project that can build the code and generate jars. Here is the GitHub Project https://github.com/snambi/GeoIP

If you need to use this library in your maven project, add the following dependency

<dependency>
   <groupId>org.geomind</groupId>
   <artifactId>geoip</artifactId>
   <version>1.2.8</version>
</dependency>

Add the following repository configuration, under "repositories" in the pom.xml

<repository>
   <id>geoip</id>
   <url>http://snambi.github.com/maven/</url>
</repository>

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