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
1. Positioning the user
Alternative positioning systems for mobile clients
Background mapping / foreground content
3. Retrieving geographically relevant content
Comparing the spatial footprints of user and content
Recent developments and future trends
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 .
 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?
Well suited for sat-nav
Network assistance has decreased time to first fix...
But weak signals – poor in dense urban / indoors
GNSS satellites are transmitting stations whose location is known
Terrestrial equivilents: WiFi access points; Cellular network base stations
Bluetooth / RFID
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)
New forms of geo-content are driving the development of location-sensitive applications
- Online map data and APIs provide context for location apps
- 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?
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
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
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
Spatial Markup examples
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
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’
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
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