Develop Reference

How to most accurately determine the location of an Android device?

I'm building an app that should be able to report the users exact location. There is only a need for a single location, i.e. I don't need to track the device continuously.
I want the location to be as accurate as possible, and it's okay to wait a short while for the location to be determined (max 1-2 minutes).
I've been looking at FusedLocationProviderClient.getLastLocation(), but since I want the location to be as accurate and updated as possible it doesn't fit my needs.
So I started looking at using FusedLocationProviderClient.requestLocationUpdates() instead, and it seems like a better choice.
But I'm not sure how to best configure my LocationRequest to get as good accuracy as possible. For instance, would it be better to use setNumUpdates() so that I only receive a single update and use that as my location, or should I receive multiple updates in hopes of getting better accuracy (GPS locking to more satellites for example)? I'm thinking that if I use the second approach, I could look at the value of getAccuracy() from each location update and only keep the one with the highest accuracy. The downside is that if the device is moving and I keep receiving updates for a minute or so, the first location could have the highest accuracy, but since it's a minute old it's not accurate any more.
As stated above, I need just a single highly accurate location and it's okay for the app to wait 1-2 minutes for it if needed. What would be the best approach in this kind of scenario?

First, make sure the accurate location is turned on. look at Settings.Secure.LOCATION_MODE_HIGH_ACCURACY It has a noticeable advantage over only using GPS. Then listen for the location for a while and calculate the result you get to find out the best location. You can also detect if the user is moving if the number differs a lot or by using Activity Recognition API. It shouldn't be very hard to write this calculate function to get the best result.
I'm not sure about this but I really don't think waiting more than a few seconds gives you an advantage. to be sure you can simply alter this time and watch the result.

You might want to use LocationManager. In my experience FusedLocation will indeed appear to lock faster but may not be as accurate overall, or at least for a while. I have an app that also requires pretty accurate coordinates. My default is to use a LocationManager based approach but users can switch to a FusedLocation provider if they want faster locking (like when indoors).
This is a good overview https://developer.android.com/guide/topics/location/strategies
For the provider when requesting updates I'd use LocationManager.GPS_PROVIDER. It will take longer to lock since it will wait for satellites and not use Wifi or other towers. But you said that's OK. Something along these lines
LocationManager locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, YourLocationListener);
Once you start getting location updates via your listener's onLocationChanged() you can start to inspect the location for accuracy, movement from last location change, etc. to try and evaluate if the GPS receiver is still settling in on a location. Once you are satisfied with the quality of the fix you can stop receiving location updates (locationManager.removeUpdates(YourLocationListener)) and then run your logic that needs the location. The link I provided has good info about this too.

Getting GPS co-ordinates quicker programmatically without internet, but using network provider and mobile GPS

I have referred many questions on this topic, but it seems some of my requirements are missing:
I want to get the GPS location at ~0.0001 accuracy
Don't want to use internet; Though GSM/CDMA network is ok
Should be obtained programmatically when the app starts
Should be quicker, say within a minute (like iPhone, which probably works in Airplane mode as well!)
The code should work in most of the devices
The phone may switch-on/off anytime and travel any distance
Is there any way to get just the co-ordinates with above mentioned requirements? Any sample code snippet will be much appreciated.
Checking various apps like "Locate Me", "Maverick", which claim to show offline locations. But in various scenarios without internet, they don't give track the location (in India).
I have referred plenty of old/new questions inside/outside SO. Below are few:
Is it possible to have the gps location while offline with the nexus
7?
Does GPS require
Internet?
How to get current exact location in android without internet
connection?
[Note: I am asking this question on behalf of my Android team and will be happy to clarify the details if asked for. Should you feel that this post belongs to Android.Stackexchange, then kindly move it.]

1. I want to get the GPS location at ~0.0001 accuracy
You can listen only to GPS provider and discard a location when it doesn't have the minimun accuracy you want:
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 5, myLocationListener); // "myLocationListener" must be an object from a class that implements LocationListener
// "myLocationListener" implementation of LocationListener.onLocationChanged
public void onLocationChanged(Location location)
{
int MIN_ACCURACY = 5; // in metters
if ((!location.hasAccuracy()) || (location.getAccuracy() > MIN_ACCURACY))
{
// discard this location and keep listening to new location readings
}
else
{
// that's a good reading!
// do somethings you want... blah, blah, blah...
// stop updates when you get the location to preserve users' battery.
locationManager.removeUpdates(myLocationListener);
}
}
2. Don't want to use internet; Though GSM/CDMA network is ok
Yes, GPS works totally off-line. Android can make use of internet ONLY to update A-GPS data cache and provide faster reads in cold-start updates.
3. Should be obtained programmatically when the app starts
Then call item locationManager.requestLocationUpdates on mainActivity's onCreate event.
4. Should be quicker, say within a minute (like iPhone, which probably
works in Airplane mode as well!)
Keep in mind that iPhone works with "high quality hardware". Android can be run on crappy devices. So it'll depend of:
The device's hardware quality;
The number of satellites that are visible in the sky at that moment;
The age of almanac and ephemeris data on gps cache;
GPS can fail to read satellites because user is inside a building or something.
5. The code should work in most of the devices
What is the oldest Android's API you want it to run?
6. The phone may switch-on/off anytime and travel any distance
I didn't get it. What is your concern about this?
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Update 1:
"...I would like to use Android 4.0 and above..."
I've tested GPS features from Android 2.3 to 5.0 devices. Everything runs pretty fine on all of them.
"...I have observed that 1 geo-coordinates based demo app which was working in other devices, din't work in my LGG3 with Android 5.0. Any idea on that?..."
Did you check GPS permissions on Android settings? (Maybe it's disabled) Or can be a hardware issue? Did you try in another similar device?
"...Suppose the GPS is showing correct location in New York,
I switch off the phone and then switch on after reaching to London,
then will it still show correct location (without internet)?..."
Sounds you're confusing things: reading a GPS location is one thing. Showing that location into a MAP is another different thing!
You don't need to be connected to the internet to do GPS location reading. But, if you want to show that location into a MAP, probably you're gonna need internet (to load map resources, etc.).
If you nedd to stay collecting GPS locations periodically (let's say, from 10 to 10 minutes), then it will be better to use AlarmManager to schedule a timer that will "finger" your app and say "hey, time to make a GPS reading!".
"...Also what is your opinion about the latest Fused API?..."
I've tested it and used it for a while, but I gave it up. It needs that Google Play Services be installed to work (not a problem, most users have it on their devices). But if you need ACCURACY (as I do), it will not work. It uses "fused sensors" (accelerometer, gps, wifi, compass, etc...) to try to get user location with minimum power possibile. Sometimes, it says you're 10 miles away from where you're really is. I couldn't make it work fine to keep the "path" where user has been. But it really saves battery.

Suggestion is to use Google Location Services
It takes the best possible and accurate location as accurate as it can at current moment. It automatically (with configuration of course) takes best current accuracy too - whatever is available GPS, network, internet, GSM/CDMA/LTE... It also cashes last known location so, basically, you know it every moment - the best what you can.
Of course you have to realize that each service provides its own accuracy and in it's own time. Look, for example, GPS Test App on Android and see how accuracy increases with time and used satellites.
Also Location Services is good for you because it simply provides coordinates - just as you asked and hides a lot of work to determine what real service to use based on time and accuracy. However, of course, if none of the services on your particular device and location can give you required accuracy then there is no way to get it. That's why services also provide accuracy measurement.
Here is another link

Use fused location API provided by Android SDK.Implement fused location in a Service and call it in your application MainActivity.

Android - Longitude and Latitude from GPS vs From the Network

I've ran into a little problem and I don't feel like I'm informed enough to overcome the hurdle.
In essence, I'd like to figure out whether someone is moving over a threshold of say, 40 kmh (~25mph). I get GPS coordinates at designated intervals and compare the distances, which all works fine.
My question is, which method of getting GPS coordinates would work best for this application? Using the Network, using GPS, or both (like, check if the network is connected, else use GPS)?
The summary is, which is the most accurate method?

I'd use the fused location api in this case. In addition, if you want to know if someone is moving you could use the activity recognition of google play services, it requires much less effort and you can even filter by activity: only with car for example (if you want to track over the 40km/h it's unlikely someone is moving on feet).

Is it possible to make a location based app?

Would it be possible to make an Android application that works based on location, for example when you get to work the app might turn off WiFi or Bluetooth or change any other system settings in order to save battery or something?
The app would require the user to enter in locations where they want the app to begin working, like their address, and when the phone sees that they have arrived at this location it will start working. I want to do this but I don't know where to start.
I already have some android app development experience.

Yes absolutely this is possible. I have worked on approx three application with same concept.
You need to create a center point and define a radius for the same.
Then you need to calculate the distance of you current location with that particular center point and if your distance is less than or equal to radius, trigger to switch on the services you want.
In android you can use
LocationManager class
For collecting the data. If you want some more help I can provide the same too.

I've played around with a concept like this on the Windows Phone for a while, and I think this would work for Android too.
Basically, you'd use the GPS of the device to detect your location, and then compare this to the locations saved by the user. If the location comes within range of a saved setting, perform an action.
GPS usage however drains battery, so you'd have to experiment a bit with making this an efficient method.

Have you tried GeoFencing, its really cool. It lets you define a center point, and a radius. Once the user enters this radius you get callback or a pendingIntent. You can do what you want in your callback.
You can get addresses of your customers and build geofence around their locations.
Edit :
If you choose to not use GeoFenceing (for what ever reason), note that LocationManager is highly buggy and unstable on most mobile phones (Samsung).
Instead use LocationClient, which takes care of all the crap LocationManager leaves with us to deal with and provides location faster, lesser battery and customized accuracy.
Edit :
If anyone tries to convince you otherwise, check this out. A video from google developers and their talk about why LocationManager sucks, and why they knew and helped us figure out the value Sensors add to the entire solution.
Edit : Design of your solution
You need 2 geofences
1) Outer, you can hard code this to a imaginary 500 m from office. From then on you can start looking for wifizones
2) Once a wifizone is found, save the gps and the distance from his address point. That is your inner radius.
1 Geofence is defined by your install, 2nd geofence is defined by your runtime.
2nd Geofence and be used henceforth to disable GPS (only incase you decide to use LocationManager). If not you wont need this, LocationClient will do what it does best.

How am I notified if I can't get any gps fix location?

For example, I am inside a building and i want to get my location with the accuracy of 0.75 (Criteria.ACCURACY_FINE) and this will use the gps if my gps is on. Since I am inside a building, gps won't work.
How can I determine if it is really impossible to get a gps fix location?
Is onLocationChanged(Location arg0) will be called even though no gps fix location was received when using LocationListener?
Is it possible to use a timeout in requesting gps location so that I can shift to network as the location provider if i can't get any location?

I see three basic possibilities:
Setup a LocationListener, and then
determine it based upon calls to
onStatusChanged. My concern here is
that I'm not sure how well android
is able to determine the difference
between OUT_OF_SERVICE and
TEMPORARILY_UNAVAILABLE. I would
hope that its based upon signal
strength, but its probably something
to test.
Simply listen to both. If you haven't
heard from the (more accurate) gps provider
in a certain period of time, then switch to the
less reliable approaches. This may consume more power
due to the requirement to monitor multiple location sources
simultaneously, but is probably the most reliable method otherwise.
Some hybrid of 1 and 2 above (gps, but switch to local if no results for a while)... this might be the most efficient, but more difficult to implement.