Information Technology Reference
In-Depth Information
14.4.2
Geo-referencing/Geo-coding Techniques
and Named Places
A number of different possibilities exist in trying to attribute a geographical context
to UGC:
users employ the features offered by social networks for geo-referencing their
own messages (either using the GPS on their smartphone, or providing additional
information);
users include in the message information which can lead to finding out a location
that they are talking from or about;
users may use none of the previous possibilities, but include an indication of their
geographical position (either current or by default) in their profiles;
users do none of the above: in this case it is not possible to gather the user's
location.
The third case has a low level of reliability. For a number of reasons, users may lie
about their current or “home” location. For example, they commonly choose their
favorite city, or a “cool” city, or a totally fictional location: on the popular social
network Foursquare we currently reside in Mordor (taken from Tolkien's “the Lord
of the Rings”), which we have placed, using the standard features offered by the
system, a few meters away from our lab.
For these reasons, in our research we do not use these kinds of location
specification (the “home” location or the current location as specified in the user's
profile).
The first case is also very easy to deal with: a geographical location (often paired
with extensive sets of meta-data, such as in the case of Facebook and Foursquare) is
explicitly provided in the messages. Thus, we are able to use it.
From the analysis of the results of our experiments, the geo-location features
offered by social networks are not very commonly used. The most common user
behavior is to either turn on the location sharing features when they download the
applications to their smartphone, or to forget about them.
From what we have been able to understand, the most location aware social
networks are Foursquare and Instagram, with respectively 92 % and 30 % of the
messages which have a location attached to them. Then comes Twitter, with 10-
15 %, according to time and context. Then Facebook: if we exclude the posts
related to events (which have a location attached to them), the percentage drops to
about 4 %, and comes almost completely from messages generated using the mobile
applications. These results are based on the messages we have collected over time
in our experiments, and vary a lot across time and context. For example, many more
messages with a location are generated on holidays and in times of vacation, and in
the case of special events, such as the riots and revolts in Cairo, Egypt, during 2013.
In this last case, for example, Twitter messages with a location specified rises up to
as much as 18 %.
