| research objectives
far the investigation of spatio-temporal patterns of people
rendered a quantitative understanding of the city. In our study, we
intend to leverage implicit spatio-temporal data (i.e. latitude,
longitude and timestamp) with the richness of people-generated
information. Our approach is to consider that uploading, tagging and
disclosing the location of a photo can be interpreted as an act of
communication rather than a pure implicit history of physical presence.
For this purpose, we retrieved from Flickr, large amounts of photo
taken by thousands of users in the world’s most photographed
cities. Based on the time, explicit location and people’s
description of their photos, we design geovisualizations. They reveal
patterns of tourists and citizens consuming a city, such as the flow of
people between city attractions (see figures below), the monuments
areas of influence or what is happening with day/night and
working/weekend periodicity. As a result, we are
- evaluating the potential of using people-generated
geotagged information to contribute urban understanding.
- studying how people explicitly position and disclose
spatio-temporal information in order to understand their use and need
of quality of location information in a urban space.
Urban computing generally
encompasses the study
of people experiencing
the city with technologies. Our approach is to benefit from
people’s experience of these services, to gain a more
thorough understanding of urban environments. In the recent years, the
large deployment of mobile devices led to a massive increase in the
volume of records of where people have been and when they were there.
The analysis of the accumulated archives of such spatio-temporal data
can derive high-level human behavior such as the estimation of mobility
mode. Evidently, urban planers, traffic engineers, tourism authorities
could profit from the pervasive deployment of new technologies to
increase the understanding of how people and crowds explicitly consume
We perceive three main domains of applicability of the processing and
visualization of these massively collected personal logs, traces (i.e.
history of previous locations):
- Provide urban planners, transport authorities and traffic
engineers with data to refine their models of citizens spatio-temporal
- Bring new perspective for decision making and policies
- Raise awareness and affect the discussion making of
individuals or of a crowd.
This project targets objectives at three levels, that would be
considered as the three main scientific contributions:
First, evaluate the potential of using people-generated geotagged
information to contribute urban understanding. Therefore, we have built
a framework to collect and analyze spatio-temporal data in urban spaces
based on user-generated content. The experiment
takes anonymous flickr users exploring cities as context.
Second, analyze how Flickr users take advantage of the accuracy feature
to geotag their images (where, what, when, history of use, overall
usage over time). By studying how people disclose location information,
we aim to understand the level of location information quality and
timeliness must be delivered in order to be useful and relevant?
Third, explore the parameters that influence successful
uncertainty visualization. The many
sources of error and imprecision in the sensed data impact the quality
and timeliness of the spatio-temporal data. By integrating the notions
of spatial uncertainty in people-movement maps/visualizations, we
evaluate techniques to visualize spatio-temporal data revealing their
Los Ojos del Mundo
(The World's Eyes) featured at the Disseny Hub
Barcelona between December 2008 and May 2009
Girardin, F., Calabrese, F., Dal Fiore, F. , Ratti, C., and Blat, J.
(2008). Digital footprinting: Uncovering tourists with user-generated
. IEEE Pervasive Computing
Girardin, F., Vaccari, A., and Ratti, C. (2008). Uncovering the presence and movements of tourist from user-generated content
. In 9th International Forum on Tourism Statistics
, Paris, France.
Girardin, F., Fiore, F. D., Ratti, C., and Blat, J. (2008). Leveraging explicitly disclosed location information to understand tourist dynamics: A case study
. Journal of Location-Based Services
2, 1, 41–54.
Girardin, F., Fiore, F. D., Blat, J., and Ratti,
Understanding of tourist dynamics from explicitly disclosed location
information. In The 4th
International Symposium on LBS &
Girardin, F. and Blat, J. (2007). Place
this photo on a map: A study of
explicit disclosure of location information
. Late Breaking
Girardin, F., Blat, J., and Nova, N. (2007). Tracing
the visitor’s eye: Using explicitly disclosed location
information for urban analysis
. IEEE Pervasive Computing
Fabien Girardin and Josep Blat
Pompeu Fabra University
Passeig de Circumval·ació, 8
08003 Barcelona, Spain [Map
E: fabien dot girardin (at) upf dot edu
Copyright © 2007,