I have an app in android using GoogleMaps API.
When i use google maps, I active gps and it find me so fast.
When i use my app, it takes some seconds, and if I'm in my house, gps dont find me. WHY ?
A short summary of my code:
locationManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
MyLocationListener = new MyLocationListener();
locationManager.requestLocationUpdates(
LocationManager.GPS_PROVIDER,
7000,
5,
MyLocationListener
);
Thx for answers and sorry for my poor english
EDIT
Thx for answers ! the problem is that i dont want to use network provider. Wifi is exelent, and 3g have a 400 meters error jejeej.
I only want to know, why google maps, using GPS, find me in 1 second with perfect position Although I stay in a house.
Your answer is "use coarse locate". If google maps use network providers befor gps, its impossible he find me so fast. :(
GPS is using satelites, When you are indoor it can't get the signal from the satelites hence it can't find location (can't get a fix).
The GPS needs signals from at least 4 satelites to get a proper fix, that usually takes a few seconds, once you already have a fix you can maintaine it very easly. therfore if you are using google maps it will get you a fix faster.
To get a better understand on how GPS works, check this link
You might want to use different location approachs for getting location indoor (coarse location could be the answer). I would also consider using the fused location by Google play services, it gives you a wrap up on the location providers and get you location based on what avilable at the time (meaning GPS, coarse - wifi or network).
You should try using Coarse locates for a quick locate followed by a fine locate to have a more accurate location. The coarse locate is usually very fast, while the fine one takes more time.
Basically, the idea is to do multiple locates and overriding the less accurate ones by the newer and more accurate locates.
You can find more info on the Android dev doc: http://developer.android.com/guide/topics/location/strategies.html
EDIT: if Google Maps is able to find you so fast, it is because you are not moving and they use the knowledge of the last location. Please read the above link that gives a lot of useful information for Location strategies (and it works very well).
Related
I am developing an application where I want to use Fused Location Provider. But I have some doubts, and couple of questions.
When GPS is off and I set priority to HIGH, does that mean that the GPS will be automatically turned on, or not?
Can I set UpdateLocation with Fused provider with HIGH priority on demand to save battery at least a little bit?
How can I know what Fused provider is using (is it a GPS or a network provider)?
And finally
Is Fused provider really the best choice for android location? Are there any negative points about it?
What is your opinion?
Thanks in advance.
When GPS is off and I set priority to HIGH, does that mean that GPS will be automatically turned on, or not?
No, it will not be turned on automatically. But if you use SettingsApi, will prompt a dialog to user and gives information that GPS is must be turned on. If user accepts it, the gps will be active automatically. Check the SettingsApi
How can I know what Fused provider is using (is it a GPS or a network provider)
If you use fused provider api with SettingsApi properly. It will make adequate the required settings for current location request.
Is Fused provider really the best choice for android location? Are there any negative points about it?
In my opinion, before fused provider you must deal with directly providers(Gps, network) But fused just asks you, "how accurate locations you wanna receive ?"
As in here https://developer.android.com/training/location/index.html stated very clearly that, the Google Play services location APIs are preferred over the Android framework location APIs (android.location) as a way of adding location awareness to your app. If you are currently using the Android framework location APIs, you are strongly encouraged to switch to the Google Play services location APIs as soon as possible. So I hope you got your answer.
I made a testing application for Gps, Wifi and Fused Location Provider and testing it for 2 days. It's better because it uses both of them and most of the time it's the one most accurate. Also, Gps data is a very noisy data that causes jittering, to solve this low-pass filter or other filters are used. One of the most successful filter used to get most accurate results is Kalman Filter. FusedLocationProvider use this filter same as RotationVector which is a fused sensor combines hardware and software. RotationVector uses accelerometer, gyroscope(if available), and magnetic field sensor to get and filter positition and azimuth data.
Location.getProvider for Gps with LocationManager returns "gps", Wifi returns "network", and FusedLocationProvider returns "fused".
When GPS is off and I set priority to HIGH, does that mean that the GPS will be automatically turned on, or not
Anything other than "Battery Saving" turns Gps on if available. This settings available on my Android 7.1.1 phone. Setting for location was different on previous versions of Android on user's side. As a developer to enable using Gps you should set mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
PRIORITY_HIGH_ACCURACY - Use this setting to request the most precise location possible. With this setting, the location services are more likely to use GPS to determine the location.
Setting Priority also determines battery use level too.
Can I set UpdateLocation with Fused provider with HIGH priority on demand to save battery at least a little bit?
Yes, you can set interval of location request in addition to priority.
mLocationRequest.setInterval(UPDATE_INTERVAL_IN_MILLISECONDS);
mLocationRequest.setFastestInterval(FASTEST_UPDATE_INTERVAL_IN_MILLISECONDS);
How can I know what Fused provider is using (is it a GPS or a network provider)?
Location from Wifi never returns true for Location.hasSpeed() but Gps returns almost always true if you are outdoors. Also location.getExtras() have satellites tag which you can check for satellites which is only available for Gps. Speed may not be correct if you are walking or as far i've read so far, i haven't tried this on car, when speed it less than 5km/h it's not very accurate. I mean if you are using FLP and last location data contains speed info it's definitely from Gps.
Are there any negative points about it?
As of Android 8.0 and above there is location retrieving limit if you do not use a Foreground Service or get location on foreground while app is not paused for both FLP and LocationManager.
Also FLP requires GooglePlayService to be available on user's device and it should be above a particular version. 10 or 11 depending on which one you use. This can be trouble if you wish to publish your apps on a country, for example China, that bans Google Play Services.
The existing answers don't say why the FusedLocationProvider is better.
It is better because the API fuses from more data sources (sensors, wifi, context, history) in an intelligent and battery-saving way. Also, Google is always improving it by adding more data sources. If your app uses it, you get those improvements for free.
I am looking to get device's location every 1 minute. I noticed the incorrect location of some devices.
With S7500 the correct location is found after 3-4 minutes sometimes or more, with HUAWEI Y530-U00 the correct location if found instantly. I used the example https://github.com/googlesamples/android-play-location/tree/master/LocationUpdates.
S7500 is not very powerful so I thought about a device limitation but it find location after a while. Maybe the code use only phone cell or internet instead of GPS and it makes location difficult.
Is there a way to improve this?
I am developing an android application in which i want to use wifi only to find user's location is it possible to find location of your device just by using Wifi ?
In this app i m trying to guide user to go from one place to another inside a building so i want exact location cell tower location or gps location will not be of any help
LocationManager.NETWORK_PROVIDER will use either Wifi or cell tower location (not GPS). If you want the best location, that would be fine GPS (wifi is the least accurate.) You can ask the LocationManager to getBestProvider and require fine GPS with:
criteria.setAccuracy(Criteria.ACCURACY_FINE);
Based on your latest comment, I think you would like to guide a user inside a building and somehow get more accurate locations than a gps location (which would probably not be accurate inside a building anyway). While there may be some specific situation in which this would be possible, I would say no, there is not a general solution that could be applied.
For Current Location, using GPS is highly recommended. Because with only Wifi, it will not be accurate. But still you can use this:
String uriName = "geo:"+ lat+ "," + lon+ "?q=my+street+address";
startActivity(new Intent(android.content.Intent.ACTION_VIEW, Uri.parse(uriName)));
This should work with roughly accuracy.
I think you want to guide the user while inside the building, if so, then I don't think that GPS or Wifi will be able to help you.
GPS provides a very fine location but require clear contact with the gps satellites in the space which won't be available inside buildings. Also the accuracy is within some meter distance which won't be effective in your case.
Cellular wifi will provide you location using the nearby cell tower which i think is self explanatory in your case. So, I don't think that both location services will of use in your case.
Prologue:
I have seen many posts regarding improving the GPS performance and accuracy in android devices.
But i am just curios and a little embarrassed at the result that my GPS tracking app gives. Especially when i compare it with the result i get from Google latitude.
Here is MY problem:
Why am i not able to get as accurate result as Google latitude on same device at the same time.
I used the 'Criteria' facility to customize my result and provider as follows
Criteria criteria = new Criteria();
criteria.setAccuracy(Criteria.ACCURACY_HIGH);
provider = locmgr.getBestProvider(criteria, true);
I am able to GPS location results with an accuracy of 800-900 meters in a testing Device : LG Optimus pro .
The Google latitude app shows a much finer result as the location of the device.
Is there any sort of caching being done by the app.. or any more finer criteria tweaks.
I really love to see my app giving an accuracy of 20 to 30 meters or more ;-)
Use Android's native location framework, it all depends on your GPS chipset and weather conditions at the time, but through LocationManager I'm usually able to get at least a 20m accuracy. Check this tutorial out.
You can specify whether or not to work with network provided location for example, which when provided by Cell-ID might be highly inaccurate but by WiFi highly misleading, both of them can help you get approximate locations when GPS satellites are not an option.
I have a mapview where I want to track the user's current location. GPS as well as 'use wireless networks' is activated in my phone settings.
Nevertheless, since I'm indoor I don't get a GPS fix, therefore the location is determined via network; wifi spot is available.
I have the Google Maps app running as well as my application running.
Strangely, the current location differes between Google Maps and my application, where the Google Maps is very accurate while in my app the location is somehow off a few 100 meters.
In my application I basically do the following (for debugging purposes now):
1) initially place one marker on the map: geopoint retrieved via locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
2) initially place another marker on the map: geopoint retrieved via locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
This will put the last known locations of both providers onto the map (eventually last known from outside my app).
3) then for the regular updates (since I don't get a GPS fix anyway indoor here), I do:
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, baseLocationListener);
You can see for the frequency and distance I pass the 0 param in both cases.
In the app manifest, the following permissions are granted:
android.permission.ACCESS_COARSE_LOCATION
android.permission.ACCESS_FINE_LOCATION
android.permission.ACCESS_MOCK_LOCATION
Actually my baseLocationListener does get called, which I see in the log, but the updated location is somehow the same as the last known current position (of LocationManager.NETWORK_PROVIDER), same lat/lng.
I thought maybe I overlooked something or missed a parameter or setting, or my code has a bug. Therefore I installed some other (3 in total) LBS apps from the Android market that also show the current user's location. The current locations displayed in those apps are equals to the one in my application - and they're all some 100 meters off - but at least all the same.
See the screenshot here:
screenshot http://img33.imageshack.us/img33/8679/mapproblem.png
http://img33.imageshack.us/img33/8679/mapproblem.png
Now I am wondering:
1) as I understand, getLastKnowLocation is system-wide and not app-wide, why are there differences between the location in Google maps and all the other apps?
2) does Google Maps not update the lastKnownLocation of a provider?
3) does Google Maps use a different custom location provider (i.e. due to licensing reasons) other than GPS_PROVIDER or NETWORK_PROVIDER as they are in the SDK?
4) how do achieve the same accurate result with the NETWORK_PROVIDER like Google Maps does?
I think I found an answer, although not a solution. It seems that the problem is in the data quality of the different map provider that are used for Google Maps and MapView in SDK, which differ.
The map tiles coordinates don't seem to be very accurate, just like in the public google maps web api / tiles.
See this screenshot for an example, where I pinned the same geo point.
screenshot http://img339.imageshack.us/img339/2793/gmaps2.png
http://img339.imageshack.us/i/gmaps2.png/
The map using the public map api is off a few hundred meters.
Seems that we just have to live with it ?! :(
I know your post is one-year old, but the answer I think is that: Google map data in China is offset or distorted. I notice that you are in South China. The China government requires that for some security reasons. Here is the Google search results.
The transformation algorithm is unknown. Probably you can Google it, and wish you good luck.
The Map and Satellite images in Google Maps is off by a couple of meters, but I don't think it should be off that much. This seems to be a couple hundred meters.
Depending on how you acquired your position will dictate what position you get. From what I understand, these are the three levels of acquisition.
GPS
Network
WIFI
GPS and Network are determined by triangulation. GPS being the most accurate.
WIFI is done using a "whois", an address is acquired and then geocoded, being completely inaccurate at times.
Some phones say they are GPS, but they are most likely Pseudo-GPS like the iPhone 1.