1. Bruce Scharlau, University of Aberdeen, 2011
Location for Mobiles
Mobile Computing
Some slides from MobEduNet
Bruce Scharlau, University of Aberdeen, 2011

2. Where… is the question answered by location
How do I get there?
What’s around me?
Where am I?
Bruce Scharlau, University of Aberdeen, 2011

3. Location needs context
Car/Walk
Bike
???
Where am I going, and how am I travelling there?
Bruce Scharlau, University of Aberdeen, 2011

4. LBS can be pulled by the client
Pull based scenarios let the user determine the interaction: get directions, find a shop, etc
Bruce Scharlau, University of Aberdeen, 2011

5. LBS push and pull the client
Push based scenarios let the service prompt the user: proximity based sending of adverts and coupons
Special
voucher for
startbucks
Bruce Scharlau, University of Aberdeen, 2011

6. Location can be determined a number of ways for mobiles
A- GPS
Satellite GPS
Enhanced 911
Cell tower ID
Local proximity for Bluetooth
Bruce Scharlau, University of Aberdeen, 2011

7. Location methods all offer different features
Real-time positioning methods
Accuracy depends on the method used
Different level of accuracy
Warm-up time
Bruce Scharlau, University of Aberdeen, 2011

8. The output of the location also differs
Location types:
Spatial term
Text description
Text description is usually expressed as a street address, including city, postal code, etc.
Bruce Scharlau, University of Aberdeen, 2011

9. Spatial terms provide latitude-longitude-altitude
Latitude: 0-90 degrees north or south of the equator
Longitude: degrees east or west of the prime meridian, which passes through Greenwich, England
Altitude: meters above sea level
Bruce Scharlau, University of Aberdeen, 2011

10. Go the ‘long way round’ to remember lat/long
Latitude = north/south of the equator
Longitude = east/west of Greenwich
Bruce Scharlau, University of Aberdeen, 2011

11. Location can be determined a number of ways for mobiles
A- GPS
Satellite GPS
Enhanced 911
Cell tower ID
Local proximity for Bluetooth
Bruce Scharlau, University of Aberdeen, 2011

12. Network based positioning uses Cell ID
Device is communicating with a Base Transceiver Station (BTS)
Current cell ID can be used to identify BTS
Accuracy depends on the size of the cell:
A GSM cell may be anywhere from 2 to 20 kilometers in diameter
Other techniques used along with cell ID can achieve accuracy within 150 meters
Bruce Scharlau, University of Aberdeen, 2011

13. Satellite based positioning
GPS is controlled by the US Department of Defense, and other systems are also coming online
Determines the device's position by calculating differences in the times signals from different satellites take to reach the receiver
Most accurate method, between 4 and 40 meters
Disadvantages:
Extra hardware can be costly
Consumes battery while in use
Requires some warm-up
„Canyon effects” in cities, where satellite visibility is intermittent
Bruce Scharlau, University of Aberdeen, 2011

14. Short-range positioning beacons use Bluetooth
Small areas like single buildings
Local area network can provide location
Bluetooth for short-range positioning
Bruce Scharlau, University of Aberdeen, 2011

15. Accuracy is dependent upon the application
Some applications don't need high accuracy:
Position information from a larger area
Others will be useless if the location isn't accurate enough:
Navigation applications
Bruce Scharlau, University of Aberdeen, 2011

16. There are also other issues to consider
Where were you at?, asks the boss.
Where is the shipment?, asks the delivery man.
What is the pattern of behaviour for this customer?, asks the network operator.
All can be answered with Location data, but should they be?
Bruce Scharlau, University of Aberdeen, 2011

17. Nokia and maps the dark horse?
Believe still long way to go with maps: generic now, tailored per context in future
Crosss-platform HERE Maps with API for developers
Combine maps with AR for more information and content
Bruce Scharlau, University of Aberdeen, 2011

18. Foursquare is like a loyalty card
Analytics and Yield management: some 500,000 registered merchants with dashboard allows merchants to claim their venue, run specials, and access a host of other data about how 15mn customers interact with their business in real-time.
Customer loyalty: Foursquare wants to be "a digital version of a stamp card." This is where check-in specials come in: Free drinks for the mayor or for the nth check-in. 
Search and Discovery: Foursquare added the Explore feature a year ago to let users search neighborhoods and garner recommendations for nearby businesses. 
Deals: Foursquare has partnered with a number of daily deal sites over the past year to provide real-time location-based deals
Bruce Scharlau, University of Aberdeen, 2011

19. Bruce Scharlau, University of Aberdeen, 2011
Location apps not easy
Facebook places is little-used by business; possibly as not mobile based app
Google Latitude not done much and more of a bolt-on to maps
Yelp both desktop (search for places to eat/drink/etc) and mobile with reviews etc, but mainly US
Bruce Scharlau, University of Aberdeen, 2011

20. Location based services aren’t corporate enough
Security and privacy policies fine for individuals, but not at business level.
People want more control over who sees where they are
Location is really another form of social media
Bruce Scharlau, University of Aberdeen, 2011

21. LBS in iOS uses location + maps
Core location provides ‘where’ someone is
Maps handled by Map Kit Framework
Geocoding to move from lat/long to place objects (address, building, etc) on map
Reverse geocoding also possible
Issue with maps at moment…
Bruce Scharlau, University of Aberdeen, 2011

22. Bruce Scharlau, University of Aberdeen, 2011
And where is Aberdeen?
What’s the latitude and longitude of Aberdeen?
Bruce Scharlau, University of Aberdeen, 2011

23. Aberdeen is west of London
°N °W
Bruce Scharlau, University of Aberdeen, 2011

24. Use Google API for location
Select Google APIs for new projects using maps and location
Otherwise your app won’t run
Bruce Scharlau, University of Aberdeen, 2011

25. Also put permissions in manifest
Need to add permissions for
INTERNET
ACCESS_COURSE_LOCATION
ACCESS_FINE_LOCATION
Bruce Scharlau, University of Aberdeen, 2011

26. Manifest also needs to specify map library
Apps with maps need to specify need as ‘true’ for com.google.android.maps library in manifest
Bruce Scharlau, University of Aberdeen, 2011

27. Map layouts need API key
Need to get Google MAPs API key to use maps in your apps – referenced in layout
This allows map tiles to be downloaded to your application
Bruce Scharlau, University of Aberdeen, 2011

28. Direction API for routes included
Can use direction API within maps API for routes
Bruce Scharlau, University of Aberdeen, 2011

29. LocationListener updates map
This is about as simple as it gets for map display
Bruce Scharlau, University of Aberdeen, 2011

30. Use DDMS tool to set location
Bruce Scharlau, University of Aberdeen, 2011

31. Geocoder library to look up location
Bruce Scharlau, University of Aberdeen, 2011

32. Bruce Scharlau, University of Aberdeen, 2011
Summary
Maps need API key to be displayed
Maps needs permissions set in manifest
Maps need API enabled
Lots of work done over network
Bruce Scharlau, University of Aberdeen, 2011

33. Location API for Java ME is JSR 179
JSR 179: javax.microedition.location package
Physical location
Orientation (compass direction)
Support the creation and use of databases of known landmarks, stored in the device
Bruce Scharlau, University of Aberdeen, 2011

34. The Location API has only a few components
Source: Nokia Location Guide
Bruce Scharlau, University of Aberdeen, 2011

35. Bruce Scharlau, University of Aberdeen, 2011
JSR 179 requires CLDC 1.1
Connected Device Configuration (CDC) or Connected Limited Device Configuration 1.1 (CLDC) for floating-point numbers
CLDC 1.0 does not support floating-point numbers
No requirements for MIDP
Bruce Scharlau, University of Aberdeen, 2011

36. Hardware determines the other requirements, ie BT, GPS, orientataion
Hardware platform determines which location methods are supported
At least one is needed for using LBS
Request providers with particular characteristics, such as a minimum degree of accuracy
Some location methods may be free; others may entail service fees
Bruce Scharlau, University of Aberdeen, 2011

37. Using Java ME the Location API starts with a Criteria
Need a LocationProvider, but can only call that once you know the criteria for choosing one: cost, accuracy, etc
Criteria c = new Criteria();
LocationProvider lp = LocationProvider.getInstance(c);
Bruce Scharlau, University of Aberdeen, 2011

38. Bruce Scharlau, University of Aberdeen, 2011
Don’t need to write any extra code to get coordinates from Bluetooth GPS
API checks for ‘best’ LocationProvider given the Criteria requirements
If it finds an ‘on-board’ device, then it uses that.
If not, then it checks the Bluetooth list of devices for a suitable one, and uses this.
Bruce Scharlau, University of Aberdeen, 2011

39. Bruce Scharlau, University of Aberdeen, 2011
With a LocationProvider you can call getLocation() to find your location
No matching LocationProvider returns null, and a LocationException if no LocationProviders are available
Location location = lp.getLocation(10); // timeout in seconds
QualifiedCoordinates qc = location.getQualifiedCoordinates();
double lat = qc.getLatitude();
double lon = qc.getLongitude();
Bruce Scharlau, University of Aberdeen, 2011

40. Get period updates on your position with LocationListener
// method added by LocationListener
public void locationUpdated(LocationProvider provider, Location location) {
QualifiedCoordinates qc = location.getQualifiedCoordinates();
double lat = qc.getLatitude();
double lon = qc.getLongitude();
String latString = Double.toString(lat);
String lonString = Double.toString(lon);
log("locationUpdated(): " + latString + " " + lonString); }
public void providerStateChanged(LocationProvider provider, int newState) {
log("providerStateChanged()");
Bruce Scharlau, University of Aberdeen, 2011

41. Use ProximityListener to find out when you’re close to a location
These only work on supported devices
Bruce Scharlau, University of Aberdeen, 2011

42. The LandmarkStore provides a location database
Easy to create a LandmarkStore
LandmarkStore.createLandmarkStore("Auction");
All LandmarkStores available to ALL Java ME apps
String[] stores = LandmarkStore.listLandmarkStores();
Bruce Scharlau, University of Aberdeen, 2011

43. Find your LandmarkStore and then add landmark
LandmarkStore ls = LandmarkStore.getInstance("Auction");
qc = new QualifiedCoordinates( , , Float.NaN, Float.NaN, Float.NaN);
Landmark landmark = new Landmark("Baseball park",
"Forest Park", qc, null);
ls.addCategory("Sports");
ls.addLandmark(landmark, "Sports");
Bruce Scharlau, University of Aberdeen, 2011

44. Find landmarks meeting set criteria using Enumeration
Enumeration ge = ls.getLandmarks(null, , , , );
while (ge.hasMoreElements()) {
Landmark found = (Landmark) ge.nextElement();
log(" " + found.getName()); }
ls.getLandmarks(double minLatitude, double maxLatitude,
double minLongitude, double maxLongitude);
Bruce Scharlau, University of Aberdeen, 2011

45. You may also be able to determine the Orientation of the device
Orientation provides an understanding of ‘North’ either as magnetic, or ‘true North’ as ‘magnetic north’ moves over time
This can be used in some devices such as the N95 as a type of ‘accelerometer’ similar to what is used in the Wii controls
Bruce Scharlau, University of Aberdeen, 2011

46. Nokia’s TouristRoute example provides a LBS and MVC study
Source: Nokia Location Guide
Bruce Scharlau, University of Aberdeen, 2011

47. TouristRoute startup follows criteria requirements
Source: Nokia Location Guide
Bruce Scharlau, University of Aberdeen, 2011

48. TouristRoute is ‘blueprint’ of sorts, but raises questions too
Uses many classes – decomposses objects and views
Might be better to use fewer, test if need performance, or other issues resolved
Bruce Scharlau, University of Aberdeen, 2011

49. Further references for Location API
IBM example that shows how to use external event tool in WTK (registration required)
Nokia tutorial also good on using its tools, and on MVC design for larger app
Bruce Scharlau, University of Aberdeen, 2011