GEOGRAPHY 176B: TECHNICAL ISSUES IN GIS

LECTURE 9: LOCATION-BASED SERVICES

1. LBS DEFINITIONS
2. WHY IS LOCATION IMPORTANT?
3. SOCIAL ISSUES
4. LOCATION TECHNOLOGIES
5. INFORMATION SERVICES
6. VR AND AR
7. AN LBS RESEARCH AGENDA



1. LBS DEFINITIONS

What is a location-based service?

an information service provided by a device that knows where it is

and modifies the information it provides accordingly

What fits this double test?
any location-measuring device
any device with GPS
any device whose location can be inferred

any device that uses knowledge of location to select, transform, modify information

What location?
location of the user, of the human-computer interface

location of the subject matter

centered on the user location?
location of the data server

location of the processing server

Is a GIS an LBS?
typically no, the GIS has no way of knowing where it is

or of modifying its results accordingly

e.g. by centering all map displays on the user's actual location

e.g. by displaying the user's actual location on map displays

Are desktop computers capable of providing LBS?
no, they typically do not know where they are

only to a timezone perhaps

Can location be inferred from an IP address?
frequently to country
IP addresses outside the US typically use the country as the major domain
e.g. .uk, .fi, .ee

but not always

the registration record for an IP address contains a street address
but it need not be the location of the computer using that IP
crawlers can sometimes determine the locations of Web pages
if they have embedded street addresses
the Internet was designed to abolish distance
Frances Cairncross, The Death of Distance: How the Communications Revolution Will Change Our Lives (Harvard Business School Press, 1997)
but location turned out to be important after all
The Revenge of Geography (The Economist, March 15, 2003)

"It was naive to imagine that the global reach of the Internet would make geography irrelevant. Wireline and wireless technologies have bound the virtual and physical worlds closer than ever"

Get Caught Mapping (Guardian March 27, 2003)


2. WHY IS LOCATION IMPORTANT?

Because the user wants to know

wayfinding

locating sample points in the field

in the absence of landmarks
navigating at sea

having fun

geocaching (http://www.geocaching.com)

tracing figures: (http://news.bbc.co.uk/1/hi/in_depth/sci_tech/2000/dot_life/1595670.stm)

latitude-longitude convergences, state boundary nodes

Because someone else wants to know
car rental agency: http://news.com.com/2100-1040-268747.html?legacy=cnet

spouse

search engines

tuning search engines to local needs
google.com redirected to google.fi if hit from a .fi IP address

ranking hits by proximity to IP address

a revenue stream
directed email
emailing to all addresses in a polygon
directed telemarketing
to all phones in a polygon
your residential phone is already geocoded for E911
intelligence agencies
Total Information Awareness

patterns in space and time can be indicative of certain types of activity

mining for misuse of credit cards


3. SOCIAL ISSUES

Do we have a right to location privacy?

who has the right to know where we are?

do we have a right to sell our location privacy?

in return for store discounts?
US law:
E911
calls from cellphones
sample story: http://www.popsci.com/popsci/science/article/0,12543,266052,00.html
Wireless Communication and Public Safety Act of 1999
``(4) to provide call location information concerning the user of a commercial mobile service (as such term is defined in section 332(d))_

``(A) to a public safety answering point, emergency medical service provider or emergency dispatch provider, public safety, fire service, or law enforcement official, or hospital emergency or trauma care facility, in order to respond to the user's call for emergency services;

``(B) to inform the user's legal guardian or members of the user's immediate family of the user's location in an emergency situation that involves the risk of death or serious physical harm; or

``(C) to providers of information or database management services solely for purposes of assisting in the delivery of emergency services in response to an emergency.''.

UK law:
Telecommunications (Data Protection and Privacy) Regulations 1999
limitations on the processing of traffic and billing data by carriers (no clear reference to location)
Regulation of Investigatory Powers Act 2001
can require recovery of location known from mobile phones (when this is part of traffic data) for intelligence purposes
Is there adequate regulatory protection for the use of location in traffic data?
who has access to the location?

how long should it be kept for?

what geographic resolution is available?

Do users have control over their location information?

What is privacy?

relates to individuals

guards against intrusion, appropriation, breach of confidence

"They are always watching you.  Use cash.  Do not give your phone number, social security number or address.  Do not fill in questionnaires.  Demand that credit firms remove you from marketing lists.  Check your medical records often.  Keep your telephone number unlisted.  Never leave your mobile phone on.  Do not use credit or discount cards.  If you must use the Internet, use someone else’s computer.  Assume that all calls, voice mail, email and computer use are monitored."
Economist 1 May 1999
Location privacy
protection of information about your current or home location in space or cyberspace

currently no explicit regulation of locational privacy

Raper essay in January 2001 GeoEurope http://www.geoplace.com/ge/2001/0101/0101tt.asp

private persona - should be absolutely protected

public persona - tradeable by consent, disconnected from the private persona


4. LOCATION TECHNOLOGIES

How to determine the location of a device (human-computer interface)?

location is entered by the user/system administrator
at system build time
point-of-sale systems
credit card transactions

store loyalty card transactions

credit card fraud applications

directed advertizing

buying habits

at application time
MapQuest user

retained by server

IP address
the business of geolocation
Quova: http://www.quova.com/services/services.html

Digital Envoy: http://www.digitalenvoy.net/

NetGeo: http://www.caida.org/tools/utilities/netgeo/

InfoSplit: http://www.infosplit.com/

GPS
direct measurement of location

better than 10m with PCMCIA card

Suunto wristwatch

assorted devices

but GPS fails
under overpasses

indoors

under thick tree canopy

in urban canyons

98% success reported on San Francisco Bay roads

20% success in Hong Kong bus tracking

supplementing GPS
with inertial navigation systems

with differential corrections (DGPS, WAAS)

Cellphone geolocation
by 2000 cellphones exceeded home PCs in Italy, Finland, Sweden, Norway, UK, Denmark, Germany, S Korea, Japan, France
US still only 40% compared with 60% homes with PCs
through GPS embedded in phone
battery consumption issues
measured by service provider
or by the device
Cell identification
positional accuracy depends on size of cell

can locate in one of three 120-degree sectors

by timing signals can locate in concentric bands outwards from tower

positional accuracy perhaps 500m
several distinct standards
Triangulation from towers
assuming signal can be received by at least three towers

several standards

location to perhaps 300m

Measurement by device
using embedded GPS combined with signals from towers
A-GPS

Qualcomm's gpsOne (http://www.spacedaily.com/news/gps-03f.html)

location to 10m

similar accuracy with enhanced signal timing E-OTD
Locations used internally by provider, or passed to external applications



5. INFORMATION SERVICES

What kinds of information services can be supported?

E911

driving directions

yellow pages

nearest pizza
trip planner
finding best public transit route from A to B
A is entered automatically from location-enabled devices
route is optimized
based on schedules

based on actual transit vehicle locations and trajectories

Helsinki example: route options, map

San Francisco example: nextbus (http://www.nextbus.com)

friend-finder
AT&T Find Friends (http://www.attwireless.com/mmode/features/findit/FindFriends/)
location-based games
based on actual locations of players

played on 3G cellphones

e.g. Undercover (http://www.ydreams.com)

a virus that turns players into terrorists

safe havens (e.g. McDonald's)

a community website (http://www.playundercover.com)

tracking
surveillance, invisible fences
pets, children, probation

Dobson's geoslavery(http://www.ur.ku.edu/News/03N/MarchNews/March5/dobson.html)



6. VIRTUAL AND AUGMENTED REALITIES

VR: replacement of the world with a digital copy

Digital Earth

view of the world constrained by the contents of the database

uncertainty
Vermeer's Geographer
Roger Downs, 1997. The geographic eye: seeing through GIS. Transactions in GIS 2(2): 111-121
AR: augmenting the senses with information
information about the area local to the user

information beyond the reach of the senses

past

future

round the corner

under the ground

information to augment or replace impaired senses
vision with sound
AR and LBS
AR systems need to know where they are
and the exact parameters of the senses
direction of view

orientation of the head

depending on the mode of HCI

display options
devices for AR
cellphone, PDA, laptop

wearables

with output device on glasses
head-mounted display




7. AN LBS RESEARCH AGENDA

Is there a need for LBS-related coordinate systems?

The US does not have a national grid
only state-specific grids
GPS
gives positions in lat/long, perhaps UTM

where am I on the map?

most maps do not show lat/long tics or graticule

how do I know where I am on a street map

if a digital street map is not integrated with my GPS?

maps are "GPS-ready"
have lat/long graticule
lat/long is cumbersome
DMS

left-most digits redundant for most people

the GO2 grid
general principles, details may vary

city-centered

e.g. Santa Barbara Courthouse

e.g. LA Courthouse

e.g. Washington Monument

"stake hammered into the ground"

stereographic projection also centered
100 km square centered

most city residents and visitors live and work in this area

first level - 10 km resolution
number columns 0 thru 9

number rows 0 thru 9

pair of digits gives location to 10km resolution

second level - 1 km resolution

third level - 100 m resolution

fourth level - 10 m resolution

interleave digits, separate by periods

e.g. 34.71.84.06

is 37800 m east, 41460 m north

rounded to nearest 10 m

city center is at 55.55.55.55

looks like an IP address

combine with city ID

e.g. SBA.34.71.84.06
a grid that is Internet-ready
Human-computer interface issues
map displays on small screens
multiple representations

annotation

ambient light

sound
for visual impairment

to avoid distraction

as input

point-and-click
Infrastructure design
access to distributed databases

middleware, wrappers

Progressive knowledge construction
adaptive and progressive sampling

metrics of completeness

Research on tracking data
dense tracking data - DTD

accuracies

relative and absolute
1 hz or better

parsing tracks and inferring activities

a null hypothesis for tracks

visualization of tracks

Research on new types of behavior
how is human behavior modified by LBS?

flocking and swarming

the smart mob
Howard Reingold, 2002. Smart Mobs: The Next Social Revolution. Perseus Publishing

http://www.smartmobs.com

European research projects

Anthony Townsend, NYU

the value of location
currently retail locations depend on visibility

in an LBS world a retailer need not be on a corner or main street to be visible