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2016) shows that social networks (e.g. Twitter, Face-
book) are the main tool for acquiring crowdsourcing
information in emergency management. This study
also shows that most tools using InfoVis apply similar
techniques, which consists of devising a set of icons
or shapes to represent the information on a map.
In our research, we argue that decision making
in emergency response may be improved by focus-
ing on presenting the most relevant information about
the emergency to the emergency managers. In our ap-
proach, we employed several heuristics to summarize
gathered information, using icons and text-based vi-
sual metaphors. We also incorporated different charts
detailing the distribution of crowdsourcing informa-
tion, which the emergency manager can use to refine
his/her judgment about the emergency.
To evaluate our InfoVis approach, we imple-
mented a proof of concept tool called Emergency Re-
sponse Toolkit (ERTK), a component of RESCUER
platform aimed to support command and control cen-
ters on analyzing information from the crowd. We
also conducted a case study with 15 experts in emer-
gency management to gather their impressions and
feedback on the proposed approach. The results in-
dicate that our approach has the potential to improve
decision making in emergency management.
The rest of this paper is organized as follows. Sec-
tion 2 discusses related works about the use of InfoVis
in the emergency management. Section 3 presents our
visualization approach. Section 4 describes the de-
sign and and execution of our evaluation. Section 5
presents our experimental findings. Finally, we draw
our conclusions and indicate future directions of re-
search in Section 6.
2 RELATED WORK
The visualization of crowd data faces several unique
challenges due to the nature, the amount and the for-
mat of data involved (Gao et al., 2011). The visualiza-
tion tool has to allow the user to gather an overall view
of the data, and also be able to drill down and look
into specific data points (Dusse et al., 2016). Crowd
data must also usually be categorized and transformed
into useful information for decision making. In this
section, we will discuss existing tools and approaches
to visualize crowd data in emergency management,
their achievements and shortcomings.
Ushahidi is an open-source platform that has been
used in several high-profile disasters such as the Haiti
earthquake. This platform provides tools for users
to load, filter and visualize crowd data from multiple
sources (email, twitter, SMS et cetera) (Heinzelman
and Waters, 2010; Duc et al., 2014). Data that ar-
rives from the available channels are gathered if they
contain one or several of predefined keywords. Ad-
ditionally, Ushahidi provides a web-based form and a
mobile app that users can utilize to input structured
data in the system.
The main visualization component of the Ushahidi
platform is an annotated map. This map allows users
to obtain a generalized view of the emergency and
clusters reports based on the level of zooming of the
map and their proximity. There is also a timeline of
the emergency and widgets that allow the user to filter
the reports by category, area and time. The clustering
strategy adopted by Ushahidi provides an adequate
view of which areas need more attention (i.e., have
more people). But sometimes results in undesirable
clutter and occlusion of informational elements.
Sahana Eden (Duc et al., 2014) is another promi-
nent open-source emergency management tool that
has been successfully deployed in the Haiti earth-
quake of 2010. Sahana Eden focuses on the pre-
paredness and mitigation phases of emergency man-
agement and has a plethora of features to organize and
manage emergency management assets (human and
otherwise) whose investigation are beyond the scope
of this paper.
Despite being used to display static information,
the map provided by Sahana Eden has filtering and
visualization categories. Nevertheless, both Sahana
Eden and Ushahidi lack the ability to represent what
is happening as anything more than points, as high-
lighted by Duc et al. (2014) .
Another platform to deal with crowdsourcing data
is presented by Wu et al. (2011), with focus on par-
ticipatory multimedia generation. This platform con-
sists of a mobile application that sends geo-tagged
pictures to a server, a web-based desktop application
(called CIVIL) that allows the emergency manage-
ment professionals to view the received information,
and server infrastructure (Wu et al., 2011).
CIVIL displays the pictures received from the
users in real-time as thumbnails on a map. The
thumbnails can be interacted with, allowing the user
to contact the sender of the picture. The desktop
interface of the CIVIL application provides: “a pri-
vate map, a public map, and a set of analysis tools
to support collaboration and decision making” (Wu
et al., 2011). Each user can make annotations and
sketches on his private map or the public map, which
is shared across all users. The analysis tools provided
by CIVIL include “a chatting panel, a table sorting
all annotations, a chart showing accumulated annota-
tions, and a timeline visualizing individual annotation
activities” (Wu et al., 2011). CIVIL also tracks the
Supporting Decision Making during Emergencies through Information Visualization of Crowdsourcing Emergency Data
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