International Journal of Geographical Information Science, 2013
Vol. 27, No. 8, 1668–1687, http://dx.doi.org/10.1080/13658816.2013.766336
Guidelines for trust interface design for public engagement Web GIS
Artemis Skarlatidou*, Tao Cheng and Muki Haklay
Department of C ivil, Environmental and Geomatic Engineering, University College London (UCL),
London, UK
(Received 6 May 2012; final version received 24 December 2012)
Attesting to the powerful capabilities and in technology trends, many scholars envi-
sioned the consolidation of geographic information systems (GIS) into vital tools for
disseminating spatial information. GIS are presently used to inform, advise and instruct
users in several contexts and to fur ther engage citizens in decision-making processes
that can impact and sustain policy development. Interaction with these applications
incorporates risk and uncertainty, which have been repeatedly identified as precondi-
tions in nurturing trust perceptions and which instigate a user’s decision to rely on a
system and act on the provided information. Research studies consistently demonstrated
that a trust-oriented interface design can facilitate the development of more trustworthy,
mainly e-commerce, systems. Trust in the Web GIS context, despite its significance, has
only relatively recently received some attention. A set of human–computer interaction
(HCI) user-based studies revealed some Web GIS trustee attributes that influence non–
experts’ trust beliefs and found that when these are problematic or absent from interface
design, users form irrational trust perceptions, which amplifies the risk and may impose
dangers to the user. These Web GIS trustee attributes that influence non-experts’ trust
perceptions are formulated here into a set of tr ust guidelines. These are then evaluated
using the PE-Nuclear tool, a Web GIS application, to inform the public about the site
selection of a nuclear waste repository in the United Kingdom. Our preliminar y results
indicate that the proposed trust guidelines not only support the development of rational
trust perceptions that protect non-experts from inappropriate use of Web GIS technol-
ogy b ut also contribute towards improving interaction with such applications of public
interest issue.
Keywords: trust; human–computer interaction; GIS; public engagement; interface
design
1. Introduction
The Internet, in particular the World Wide Web (the Web), is f ast becoming an inte-
gral part of our daily lives and an essential medium for satisfying ever yday needs. The
Web has played a determinant role in the dramatic shift of the traditional cartographic
landscape and contributed decisively towards the ubiquitousness of geospatial products
(Miller 2006). The so-called ‘Geospatial Web’ (or GeoWeb), with its Web GIS applica-
tions, holds a prominent position in the wider sphere of cyberspace (Haklay et al. 2008).
Web GIS – simply and broadly defined as the applications that allow users to browse, view
and occasionally contribute geographical information and perform geospatial analysis –
*Corresponding author. Email: a.skarlatidou@ucl.ac.uk
© 2013 The Author(s). Published by Taylor & Francis.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License http://creativecommons.
org/licenses/by/3.0/, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is
properly cited. The moral rights of the named author(s) have been asserted.
International Journal of Geographical Information Science 1669
are routinely used in several contexts, from map mash-ups incorporated into a thematic
diversity of Websites (Haklay et al. 2008), and public mapping applications (e.g. Google
Maps) to support way finding tasks, to more advanced Web GIS applications that support
different levels of public engagement in governmental decision making.
Scholars in the Public Participation GIS field have demonstrated that GIS (e.g. Carver
2001, Sieber 2006) and Web GIS (e.g. Steinmann et al. 2005) can facilitate and potentially
enhance public engagement and participation in spatially related problems. Within this
context, indicative examples, although we acknowledge that in their majority exemplify
one-way communication, include The UK Environment Agency’s What’s In Your Back
Yard (WIYBY) application,
1
which provides information about a range of environmen-
tal issues; UK Department of Environment, Food and Rural Affairs (DEFRA) England
Noise Mapping,
2
which provides access to model output of urban noise; Health Profiles
provided by the UK Association of Public Health Observatories
3
; London Metropolitan
Police Crime Mapping,
4
which notably crashed on its launch date due to an unexpected
level of demand (i.e. 18 million hits/h) (Travis and Mulholland 2011). Undoubtedly, Web
GIS have fast become major tools for the dissemination of spatial information that inform,
advise and instruct users. This information and the tools that are used to make it publicly
available should be usable, rational, but also trusted (Coleman and Gotze 2001, Wong and
Chua 2001, Fogg 2003).
Risk and uncertainty are trust preconditions (Chopra and Wallace 2003) that are inher-
ent to specific contexts of Web GIS use (e.g. environmental decision making), and therefore
to situations in which a wrong decision to trust a Web GIS application and the information
that it incorporates may have severe consequences to a user’s health and financial status
(e.g. incorrect assessment of flood risk which may lead into buying an inappropriate home
insurance). Risk and uncertainty are further increased due to end users’ limited or lack of
GIS knowledge and expertise (Unwin 2005). Non-expert users may not be knowledgeable
in assessing GIS or spatial data handling and accuracy issues or in assessing the correct
implementation of cartog raphic design principles (e.g. scales and projections), which may
tamper the map content with the occasional intention to misinform users (Monmonier
1996). Web GIS applications can now be created by developers who have the enthusiasm
and technical knowledge (e.g. API development skills) but who at the same time lack the
essential cartographic and GIS skills. Consequently, relying on the skill of the developer
alone amplifies the risk and further escalates this problem. In addition, a large and growing
number of studies demonstrate that there are non-expert users who have difficulty in using
Web GIS applications due to specialised functionality that increases interface complexity.
This differentiates Web GIS interaction from the conventional online browsing experience
(Steinmann et al. 2004), but also these additional usability interaction barriers may further
impact trust.
People’s trust perceptions of electronic online environments influence their intentions
to engage, use and accept these systems, enhance cooperative behaviour and influence the
perceived user experience (Shneiderman 2000, Egger 2001, Fogg 2003). Thus, it is not
surprising that, within the online context, trust has been the subject of extensive research.
Studies, mainly in the e-commerce domain, have demonstrated the impact of specific trust
guidelines in the design of more trustworthy systems (Shneiderman 2000, Fogg 2003).
While these guidelines are useful for the e-commerce context, previous studies demon-
strated that Web GIS have distinct user aspects, including the interaction with the GIS
component, that influence non-experts’ trust perceptions (Skarlatidou et al. 2010a, 2011a,
2011c).
1670 A. Skarlatidou et al.
This article introduces a set of trust guidelines to improve trust in Web GIS. We start
with a brief overview of online trust and its components and then briefly review a set
of studies that revealed the Web GIS trustee attributes that influence non-experts’ trust
perceptions. These trustee attributes are used to formulate the trust guidelines presented in
Section 3. Section 4 discusses the procedural framework of the evaluation experiment, and
Section 5 presents the preliminary evaluation results, which show that the guidelines can
assist non-experts in the development of rational trust perceptions when they interact with
Web GIS. Section 6 concludes with a discussion of the findings and suggestions for future
trust-based research in Web GIS.
2. Background: online trust and trustee attributes
Trust has been a subject of research in several disciplines and, as such, various trust defini-
tions exist (Shapiro 1987). Despite the lack of a commonly agreed definition, specific trust
components exist in any trusting relationship, which are illustrated in Figure 1. Any trust-
ing relationship involves always two parts: a trustor and a trustee (Grabner-Kräuter and
Kaluscha 2003). The tr ustor is a person, while the trustee may take the for m of another
human collaborator, an organisation or a computerised system, since humans respond
socially to technology (Lee and See 2002, Fogg 2003). These two parts interact in such
a way that the trustor is willing to depend on the trustee, with the confidence that the
trustee will act on the trustor’s best interests (Kini and Choobineh 1998). This ‘willing-
ness to depend’ is the first trust precondition; if the trustor is not willing to rely on the
trustee, then there is no reason to develop trust perceptions or there is distrust, a concept
with different implications. Risk and uncertainty are also trust preconditions, as Trust is
only needed, and actually flourishes, in an environment that is uncertain and risky (Wang
and Emurian 2005, p. 111). The trustor’s decision to trust and thus depend on the trustee
is influenced by the trustor’s propensity to trust and the trustor’s trusting beliefs (cognitive
Properties
Attributes
-Trust preconditions-
Risk, dependence, uncertainly
1. Propensity to
trust
2. Trusting beliefs
Trustor
(person)
Trustee
(online
system/
information)
TRUST
-Context specific-
Affective and cognitive trust
Functionality,
perceptual\
attributes and
trust cues
(e.g. udability,
aeshetics, seals
of approval)
Figure 1. Trust and online trust components (Skarlatidou et al. 2011a).
International Journal of Geographical Information Science 1671
and affective) of the trustee. Trusting beliefs are influenced by the trustee attributes (e.g.
the trustor’s integrity and honesty if the trustor is another human collaborator).
The trustee attributes may vary according to the identity of the trustee (e.g. is the trustee
a relative, a friend or a computerised system?). Particularly with respect to online trust,
research in the discipline of human–computer interaction (HCI), which is concerned with
the design, evaluation and implementation of interactive computing systems for human use
and with the study of major phenomena surrounding them (Hewett et al. 1992, p. 6), has
found that understanding the trustee attributes of a system that influence the trustor’s trust
perceptions can facilitate the design process of more trustworthy systems (Fung and Lee
1999, McKnight et al. 2002, Chopra and Wallace 2003, Fogg 2003, Grabner-Kräuter and
Kaluscha 2003).
The trustee attributes described in the online trust literature can be differentiated
between perceptual and functional. The former refers to the source and its reputation,
and the latter is associated with evidence collected through interaction with the trustee
and assessment of its quality (e.g. its aesthetics and usability). It should be noted that we
use the term ‘functional’ because this category includes attributes that could be designed
in such ways that improve interaction with the application (e.g. improving beauty through
simplicity). A trust-oriented interface design aims at improving these attributes and also
proposes the use of trust cues. Trust interface designs have been previously summarised
in different sets of e-commerce trust guidelines such as those developed by Egger (2001),
Fogg (2003) and Wang and Emurian (2005). Indicatively, Wang and Emurian’s (2005)
four-dimensional model proposes guidelines such as the use of pastel and cool tones (a
functional trustee attribute that refers mainly to the Website’s aesthetics), usable navigation
techniques (a functional trustee attribute that refers to the Website’s usability) and incorpo-
ration of interface design features that create an atmosphere of social presence (trust cues
such as testimonials, chat rooms, blogs and forums).
In the Web GIS context, a set of studies recently attempted to identify the trustee
attributes that influence non-experts’ trust perceptions following an HCI-based, inductive
research approach. Firstly, the UK Environment Agency’s WIYBY application and the
Spatial Decision Support System (Nuclear-SDSS
5
) ‘Where to dispose of Britain’s Nuclear
Waste’ provided by Leeds University were examined using the HCI inspection methods of
Heuristic Evaluation and Cognitive Walkthrough (Skarlatidou et al. 2010a). The authors
found that more than half of the general problems detected by three expert evaluators were
considered as trust-related, and the majority of them were rated as critical. The detected
problems unveiled the importance of specific Web GIS trustee attributes such as the use
of effective menu structure and design, use of effective map colour combinations, consis-
tency in GIS functionality and effective design and use of legends and scales that efficiently
support user tasks.
The same applications were further examined using HCI empirical testing methods
of Usability Testing and Cooperative Evaluation with the further involvement of 30 non-
expert users (Skarlatidou et al. 2010b, 2011b). These s tudies reveal that participants
encountered significant problems while interacting with both applications, which resulted
in a poor user experience (e.g. I was unenthused by the Website [WIYBY] and found it
a bit frustrating. Probably wouldn’t use it again if could avoid it; I felt frustrated and
disillusioned at the end of this [for Nuclear-SDSS]); yet in their majority they stated that
they trusted the applications (e.g. I would trust information coming from a government
Agency on principle [for WIYBY]; Academics are probably more trustworthy as they have
a degree and I believe that the system is trustworthy [for Nuclear-SDSS]). Despite the
high influence of the perceptual attributes in the formation of overall trust perceptions,
1672 A. Skarlatidou et al.
participants provided recommendations as to how specific trustee attributes should be
designed to improve their trust (e.g. use of big map sizes; use of effective colour com-
binations to support effective map interpretation; provision of high quality and effective
legends; incorporation of trust cues such as logos visible on all pages, map tutorials, blogs
and external links).
To clarify the design implications of specific trustee attributes (i.e. map size, colours,
scales, legends, map tutorials, use of logos and provision of data information), Skarlatidou
et al. (2011c) carried out a set of additional experiments that further involved the London
Air Quality Network (LAQN
6
), London Profiler (LP
7
) and England Noise Mapping
(ENM
2
) applications. It was found that non-expert participants completely ignored impor-
tant trust cues (e.g. metadata) and they formed their trust perceptions purely based on
interface design elements. This finding is supported by the fact that although the LAQN
application updates data every two hours from monitoring sites, an impor tant cognitive
trust cue, this information was missed by participants due to ineffective design in commu-
nicating data issues. Instead, the participants showed greater levels of trust towards the LP
application where the design of specific trustee attributes (e.g. map size, colours and leg-
end) improved trustworthiness despite the fact that the data were not updated beyond the
original design of the application. Amongst several recommendations, the authors suggest
the use of distinct colour combinations (e.g. a red/blue/green colour scheme) that comply
with basic cartographic design principles and a map size larger than 400 × 600 pixels,
which improves readability and confidence in map interpretation and trust (as opposed to
an orange/brown colour scheme and smaller map size which reduce trust).
To summarise, Web GIS trust investigations unveil the existence of specific trustee
attributes that influence non-experts’ trust perceptions, and suggest that when these are
problematic, ‘hidden’ or completely absent from the interface design, non-experts tend to
form rather irrational trust perceptions based on the application provider’s identity or based
on interface design features. These trustee attributes set the foundations for the develop-
ment of a set of Web GIS trust interface design guidelines, which are discussed in Section 3.
It should be noted that the proposed trust guidelines focus only on the trustee attributes that
non-expert users thought are important for the formation of their trust perceptions and they
derived from mainly the environmental Web GIS context.
3. Trust guidelines
Wang and Emurian’s (2005) trust model for e-commerce is modified to accommo-
date the proposed Web GIS trust guidelines. The tr ust guidelines are organised into
five design dimensions, namely, graphic, content, structure, functionality and trust cue
designs. As Web GIS applications are usually integrated within Websites of a broader
context and interest, the first four design dimensions propose trust guidelines separately
for the Website’s user interface (UI) (Appendix, Table A1) and the GIS component
(Appendix, Table A2). The tr ust cue design dimension incorporates guidelines with respect
to additional interface design elements that can be incorporated in Web GIS to improve
trust.
3.1. Graphic design
The graphic design dimension aims at improving the graphic design quality of the UI
and GIS visualisations with respect to the trustee attributes that evidently influence non-
experts’ trust perceptions, such as colour combinations and map size. Specifically, these
