Upcoming SlideShare
Loading in...5







Total Views
Views on SlideShare
Embed Views



0 Embeds 0

No embeds



Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
Post Comment
Edit your comment
  • Demos to prep: - yahoo pipes - rss feeds
  • Comparing key characteristics of mobile users top requirements to highlight importance of spatial / local information
  • Things are coming together Tony Benn…
  • Linking theme – for local / location-aware search, position of content must also be known Key mes – information now has its place!
  • Linking theme – for local / location-aware search, position of content must also be known Key mes – information now has its place!

ppt ppt Presentation Transcript

  • Location Based Services (LBS)
    • Positioning, Geocontent and Location-aware  Applications
    • What have we learnt? Where are we now? What’s around the corner?
  • David Mountain – Bio
    • Researcher / Lecturer at City University
      • Research interests in GI science and location-based services since 2000
      • Early LBS prototypes: WebPark -> Camineo
    • Technical director of Placr Ltd
    • Start-up offering products and solutions for mobile, location-aware systems since 2008
  • LBS requirements
    • 1. Positioning the user
      • Alternative positioning systems for mobile clients
    • 2. Geocontent
      • Background mapping / foreground content
    • 3. Retrieving geographically relevant content
      • Comparing the spatial footprints of user and content
    • Recent developments and future trends
  • Abstract
    • For over ten years, market analysts have been predicting the imminent mass consumer take-up of Location-Based Services (LBS) . Whilst location-technologies have performed strongly for some niche applications - such as dedicated personal navigation 'Sat-Nav' devices LBS applications on mobile phones have tended to be the preserve of the digerati. Over this time, the barriers that have prevented LBS being taken up by a more mainstream audience have been overcome , and  we are finally seeing the long-promised growth i n terms of application, number  of users and revenue. This talk will consider why LBS are finally accessible to the mainstream, future trends , and the challenges that remain for mobile, location-aware search .
  • [1] Position Determining Technology (PDT) Usually based on signals in the electromagnetic spectrum (1) lookup location of strongest transmitter, and assume you are there (2) lookup location of all transmitters and triangulate based on distance (transit time of signals) (3) map frequencies of signals from all transmitters from all locations (fingerprinting)
  • Global Navigation Satellite Systems
    • Satellite systems which depend upon hardware in orbit around the earth (space segment)
    • Other components include:
      • a system of ground stations (control segment)
      • handheld receivers (user segment)
  • Global Navigation Satellite Systems
    • GPS: The Global Positioning System
    • Synonymous with GNSS and positioning systems, the most widely used system
      • chipsets from $1; widely integrated into PNDs and phones
      • free at the point of use
    • GLONASS: from Russian Govt / Space Forces
      • Limited investment in 90s, and fewer receiver chipsets. Can augment GPS
      • Free at the point of use
    • Galileo Services: EU system operational 2013(?)
    • - Range of services: Open, Commercial, Safety of Life, Search and rescue (transmission), public regulated service
  • Why use GNSS / GPS?
    • Global coverage
    • Well suited for sat-nav
    • Network assistance has decreased time to first fix...
    • But weak signals – poor in dense urban / indoors
  • Alternative infrastructures
    • GNSS satellites are transmitting stations whose location is known
    • Terrestrial equivilents: WiFi access points; Cellular network base stations
    • Bluetooth / RFID
    • IP lookup
  • Hybrids
  • Positioning APIs
    • Many alternative PDTs: problem for developers?
    • W3C Geolocation API specification
      • Opera / Firefox browsers
    • Location Managers from Android / iPhone
    • All aim to provide a single interface for all PDTs available on any given device
    • Massive leap forward for LBS (consumer proof)
  • PDT where next?
    • Are we nearly there yet?
    • Indoor still a problem
    • Different LBS have different PDT reqs:
      • Weather reports; buddy finder; around me; pedestrian navigation; augmented reality
    • More reliable accuracy information
    • How to match requirements of app with profile of PDT (eg accuracy, availability, power consumption, bandwidth)
  • [2] Geocontent
    • New forms of geo-content are driving the development of location-sensitive applications
    • Background mapping:
    • - Online map data and APIs provide context for location apps
    • Foreground content:
    • - Georeferenced info and POI Dbs provide content for local search
    • - documents, multimedia, blogs, new articles, physical features, etc..
    • In what ways can information be geographically relevant?
  • POI databases
    • Until recently, the dominant form of geo-content
    • Databases of features storing geometry, attributes, and categories
    • Search combination of category / keyword and current location
    • Tend to focus on facilities / services (cf Yellow pages) rather than information (cf guidebook)
    • Brand provides a service guarantee
    • Data retrieval
  • POI databases Searching within categories Most popular (mCommerce)
  • OS PointX dataset
  • Structured data on the web
    • Standardised data formats being used by content providers to publish frequently updated information
      • Eg web feeds dynamic content
      • Increasingly information available with semantic structure (cf xml vs html)
    • Web feeds now widely viewed, using feed readers , or web browsers, checking periodically for updates
    • Really simple syndication (RSS) most widely used format, but there are others (e.g. ATOM)
    • Many content providers now provide an RSS feed: BBC, Reuters, Stephen Fry blog, City University London
  • Spatial mark-up
    • Many XML-based languages allow geographic information to be represented:
      • OGC Geography Markup Language (GML)
      • Google’s Keyhole Markup Language (KML)
      • Wiki formats using |coord|
      • GeoRSS: geographic referencing in RSS feeds
      • GeoJson
  • Spatial Markup examples
  • GeoRSS feeds
    • Simple to integrate into web maps using mapping APIs
    • Services are emerging which aggregate spatial content: map mashups:
      • Flickrvision: http://www.flickrvision.com/ overlays flickr’s most recent GeoRSS feed on Google Maps
      • Twittervision: http://beta.twittervision.com/: does the same for Twitter
    • KML and GeoRSS content can be published as layers in Google Earth
    • Increasing volumes of geo-content are now available this way
  • Google Earth GeoContent
  • Geocoding free text data
    • How do we spatially enable the whole web?
    • Geoparsers can recognise placenames in natural language documents
    • Geocoders can find the coords associated with those placenames.
    • But how do we disambiguate?
      • I was reading in Reading
      • I stoke the fire
      • I am reading a book by Jack London
  • Volunteered Geographic Information
    • Connected, location-aware mobile devices have allowed people to become producers, as well as consumers of geographic information
  • Open Source Spatial data
    • Since 2005, OpenStreetMap (OSM) has been creating an open source map of the world.
    • Bottom up approach: features are tagged, no formal attributes. No formal definition of what will be surveyed, to what level of accuracy, how this will be done, or frequency of update
    • Sources include enthusiastic amateur surveyors, and public available data
  • Growth of OpenStreetMap 1mn users, 1bn points
  • OpenStreetMap (OSM)
    • Impressive growth in users and coverage
    • Quality measured by ‘completeness’: number of features they have for a region compared with alt suppliers
    • By mapping regions and features that other orgs ignore, they can surpass 100% ‘completeness’
  • St Albans: Ordnance Survey vs OSM
  • Kinshasa: NavTeq vs OSM
  • Geocontent from social networking sites
    • Twitter: georeferenced moods / opinions / observations
    • Facebook: geography of social networks / budy finders / flash mobs / swarming
    • Trip advisor: accomodation ratings and reviews
    • Realtime Rome: where are the crowds flocking to?
    • Stumble upon: personalised serendipity
  • Challenges for geocontent
    • Spatially referencing free text documents: recognising and disambiguating placenames
    • Indexing spatial information
    • Combining rankings based on keyword search and geography.
  • [3] Retrieving spatially relevant content
  • Location can make mobile apps more intuitive
  • Filtering Geocontent Spatial proximity Temporal proximity Speed heading prediction Visibility
  • Scenarios of use Filter Spatial relation Criteria Example query scenario Spatial proximity Near Euclidean distance Breaking news stories within 10km of present location Temporal proximity Near Travel time Toilets within 10 mins of here Prediction Near Likely future locations Restaurants I may pass in the next hour Visibility Visible Viewshed Mountain peaks I can see from present location
  • Travel time filter: 0600
  • Travel time filter: 0900
  • Travel time filter: 1200
  • The future
    • A world where you are the search engine?
    • Applications which regularly repeat searches for content matching your trigger phrases, based on location
      • E.g. a walk around central London searching for ‘Great Fire’, or Banksy
      • Combining rankings based on theme, location and the reviews of likeminded people?
    • Some info needs may expire, some may endure
  • Searching Google Earth community pages for Banksy in London
  • Rummble: trust network
  • Rummble: bespoke results