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Location-aware applications: an overview

Location-aware applications: an overview. 12.3.2013. Content. Part I: What are L ocation- A ware A pplications? Examples of LAA s Part II: Mapping Positioning. Part I. Location-aware applications Background Key components Example apps. Location-aware application. Location

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Location-aware applications: an overview

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  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

  9. LBS as an intersection of technologies

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

  11. Limitations Computing 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 Battery 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 Small displays • Smartphone have 3”-4.5” displays • Tablets have 7”-10” displays • Most of the displays are difficult to read in sunlight

  14. Limitations Access 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 Weather 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 Nokia Transport (link) GoogleMaps (link)

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

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

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

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

  27. Augmented reality Nearest Subway (link) Layar (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

  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 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)

  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

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

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