1. Location-aware applications: an overview 12.3.2013

2. Content Part I: What are Location-Aware Applications? Examples of LAAs Part II: Mapping Positioning

3. Part I Location-aware applications Background Key components Example apps

4. Location-aware application Location Determines user's location Information Provides information spatially related to user's location Interaction Offers two-way interaction with the information

5. Location-aware application Location Determines user's location Information Provides information spatially related to user's location Interaction Offers two-way interaction with the information

6. Location-aware application Location Determines user's location Information Provides information spatially related to user's location Interaction Offers two-way interaction with the information

7. Terminology Location-Based Service (LBS) Conceptually same as LAA Used in less technically oriented context Geographic Information System (GIS) A system for storing and manipulating location- based data Are used for building LAAs

8. GIS vs. LBS/LAA GISLBS/LAA Evolutionduring several decadesquite recently User groupsexperienced usersnon-professional users Functionalitywide collection of functionalitylimited functionality Requirementsextensive computing resourcesrestrictions of mobile computing environment (computational power, small battery run time)

9. LBS as an intersection of technologies

10. Devices Single-usage Multi-usage tolling unit PDA alarm unit navigation system smart phone tablet

11. Limitations C omputing and memory resources -Top tablets and mobile phones have 1.5-2.0 GHz dual-core or quad-core processor -Average devices have approx. 1 GHz single core processor and 512 MB / 1 GB RAM -Mobile architecture is optimized for low power consumption -Modern mobile operating systems allow applications to run in background, but with a lot of limitations

12. Limitations B attery power -Intensively using internet (3G or WLAN) along with GPS discharges a full battery in 3-5 hours -Intensively using battery heats up the device

13. Limitations S mall displays -Smartphone have 3”-4.5” displays -Tablets have 7”-10” displays -Most of the displays are difficult to read in sunlight

14. Limitations A ccess to communication networks -3G/4G coverage is not everywhere -Even GSM is not available everywhere -WLAN access for positioning lacks outside bigger cities

15. Limitations W eather influences on usability -Most of the devices are not waterproof -Most of the displays are difficult to read in sunlight -Touchscreen devices are difficult to use in low temperatures (touchscreen gloves are not warm enough for -20°C) Photo: www.leavemetomyprojects.com

16. Communication networks

17. Positioning technologies

18. Content providers

19. How to use? Where am I? Where are my friends? What is here around me?

20. User actions Localization Locating yourself Navigation Navigating through space, planning a route Identification Identifying and recognizing persons or objects Event check Checking for events; determine the state of target

21. Categories of LAAs Navigation (automotive routing systems) Information (location-based yellow pages) Tracking (wildlife tracking) Games (capturing the flag) Emergency (personal alarm units) Advertising (location-based SMS) Billing (automotive tolling units) Management (inmate tracking systems)

22. Navigation GoogleMaps (link)link Nokia Transport (link)link

23. Services and recommendations TripAdvisor (link)link Yelp (link)link

24. Tracking Sports tracker (link)link Endomondo (link)link

25. Social networking Facebook places (link)link FourSquare (link)link

26. Games Shadow Cities (link)link O-Mopsi (link)link

27. Augmented reality Layar (link)link Nearest Subway (link)link

28. Part II Coordinate systems Mapping Positioning technologies

29. Coordinate systems Used to pinpoint a location on the Earth A set of numbers or letters Geographic or projected Spherical or planar

30. Geographic coordinate system Uses a three-dimensional ellipsoid surface Ellipsoid defines the size and shape of the Earth model A point is referenced longitude and latitude (angles measured from the earth's center to a point on the earth's surface)

31. Reference ellipsoid The shape of the Earth is not symmetric A reference ellipsoid can be used as an approximation International and national standards used

32. Geographic coordinate systems (GCS) Different ways to fit an ellipsoid to the surface of the Earth → many different GCSs NameContextOrganizationUsage WGS84GlobalUS Department of Defense GPS KKJFinlandNational Land Survey of Finland National mapping ETRS89EuropeEuropean UnionContinental mapping

33. Projected coordinate systems Defines a flat, two-dimensional surface based on a GCS Transforms ellipsoid coordinates to flat, planar coordinates

34. Three basic techniques Azimuth Preserves directions from a central point Not used near the Equator Conical Preserves shapes Sizes distorted Used for mid-latitude areas Cylindrical Preserves shapes Sizes distorted Used for world maps

35. Projected coordinate systems ProjectionTypeProperty MercatorCylindrical Preserves directions Used in most applications: Google Maps OpenStreetMaps Gall-PetersCylindricalPreserves areas Azimuthal equidistant AzimuthalPreserving distances EquirectangularCylindricalCompromises http://en.wikipedia.org/wiki/List_of_map_projections

36. Distance The Haversine formula

37. Positioning technologies Cell tower triangulation and cell ID databases Satellite navigation Wireless positioning systems

38. Cell tower triangulation More cell towers available = better accuracy Low accuracy where are few cell towers (1-20 km) Accuracy in cities approx. 50-200 meters No altitude information

39. Cell ID databases Each base transceiver station has an unique ID Mobile device gets associated with the BTS it is connected to (usually the nearest one) Approx. of the location can be known by using a database for BTS IDs

40. Satellite navigation (GPS) De facto standard for positioning in LBS Controlled by US Department of Defense Can be enhanced by additionally using Glonass (Russia) or Galileo (EU, in development) Accuracy 5-50 meters Does not work indoors

41. GPS accuracy test (2009) Nokia 61102.73m Nokia N95-2, cover open 3.13m Nokia N95-1 + external (Pretec) 3.61m Garmin wrist-GPS (1s.) 3.69m Garmin wrist-GPS (8s.) 3.75m Nokia E72 3.76m Nokia E66 5.10m Nokia N95-2, cover closed 6.05m Nokia N95-2 + external (Fortuna) 6.44m

42. Assisted satellite navigation (aGPS) Combines GPS with cell tower triangulation and other techniques Speeds up the process, especially time to first fix Improves accuracy Uses additional data downloaded from a server to improve accuracy Still does not work indoors

43. Wireless positioning systems Same logic as in cell ID positioning Uses wireless routers, corresponding IDs and databases Popular before GPS chips became common Example: Google Maps cars record positions of wireless networks with recording Street View data

44. Comparison of positioning technologies MethodProsCons Cell tower triangulation - works indoors - works globally (western world) - pretty accurate in cities (100 m) - inaccurate in rural areas (1-10 km) Cell ID database - no receiver needed on device - works globally (western world) - good accuracy in cities - 3rd party database needed for IDs - inaccurate in rural areas Global Positioning System - works globally (rural & city) - good, consistent accuracy (10 m) - commonly supported - doesn't work indoors - weak accuracy in cities ('canyon effect') - consumes battery life - slow initialization (30-60 s) Assisted GPS - speeds up initialization - improves accuracy - not commonly supported on devices other than smart-phones - lack of standards - requires internet connection Wireless positioning - works indoors - accurate in cities - WiFi receiver needed on device - doesn't work in rural areas or areas without WiFi - 3rd party database needed for IDs

45. References Part I: S. Steiniger, M. Neun and A. Edwardes: Foundations of Location Based Services (link)link Used with permission from the authors Part II: ICSM: Fundamentals of Mapping (link)link CC BY 3.0 AU