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54
GAIA 32/S1 (2023): 54 – 63
RESEARCH | SPECIAL ISSUE: SUSTAINABLE DIGITALIZATION
Urban planning can be understood as the process of mak-
ing decisions to shape and guide the future of our cities –
for example, in terms of settlement structures, infrastructures,
buildings, and open spaces. For this purpose, planners develop
planning concepts and strategies and then present and discuss
initial ideas and proposals with interested stakeholders and pol-
iti cians. In doing so, planners are required to take into account
the broader social, ecological, technical, and economic trends
and developments as well as locally specic conditions for hous-
ing, work, culture, and leisure. Thus, such concepts and plans
may include ideas to improve the health conditions or the qual-
ity of life in specic neighborhoods by, for example, redesigning
streets to foster cycling, building more aordable housing, or in-
creasing the number of parks for families in working class neigh-
borhoods.
Numerous actors with dierent interests are involved in these
urban development processes, with or without prior knowledge
of legal regulations, planning instruments, ecological conditions,
the cubature of buildings, or similar aspects. Hence, the (visual)
information provided to participants needs to be easy to under-
stand (Kikuchi 2022). In this context, spatial imaginations of ur-
ban streets, buildings, and neighborhoods have played a major
role in public participation in urban development (Höhl and Bro-
schart 2015). Visualization is considered the key for successful
participation, as it provides all participants with a shared basis or
language (Al-Kodmany 1999, 2002). Consequently, appropriate
visual representations are crucial for the building of public opin-
ion and decision-making (Boos et al. forthcoming).
Traditional and analog ways of visualizing and communicat-
ing new planning concepts and projects include the preparation
of maps, blueprints, and paper-based drawings, often accompa-
nied by photographs and/or physical models to optimize illustra-
tions of the planned project. The succeeding generation of plan-
ning or visualizing instruments then incorporated geographical
information services (GIS) and computer-aided design (CAD) to
map land use, visualize the dimensions of design in a digital en-
vironment, and oer perspective three-dimensional (3D) sketch-
es. Finally, 3D city models, based on 3D geospatial data, repro-
RESEARCH ARTICLE
Using augmented reality in urban planning
processes
Sustainable urban transitions through innovative participation
The use of augmented reality applications in urban planning improves the quality of participation processes and contributes to
sustainable city development. However, as our case studies also show, these potentials are not fully exploited yet as augmented reality
is not yet used in all planning phases.
Frank Othengrafen , Lars Sievers , Eva Reinecke
Prof. Dr.-Ing. Frank Othengrafen | TU Dortmund University | Department of
Spatial Planning | Dortmund | DE | frank.othengrafen@tu-dortmund.de
Lars Sievers, MSc | TU Dortmund University | Department of Spatial Planning |
Dortmund | DE | lars.sievers@tu-dortmund.de
Eva Reinecke, MSc | TU Dortmund University | Department of Spatial Planning |
Dortmund | DE | eva.reinecke@tu-dortmund.de
© 2023 by the authors; licensee oekom. This Open Access article is licensed under
a Creative Commons Attribution 4.0 International License (CC BY).
https://doi.org/10.14512/gaia.32.S1.9
Received May 16, 2022; revised version accepted January 20, 2023 (double-blind peer review).
Using augmented reality in urban planning processes.
Sustainable urban transitions through innovative
participation
GAIA 32/S1 (2023): 54 – 63
Abstract
Sustainable urban development requires innovative approaches and
concepts that involve people not only in planning processes but also in
inuencing the design of urban space. Modern formats, such as
augmented reality (AR), can help to increase the motivation for
participation and present dierent planning concepts more realistically
through dierent forms of visualization. Based on case studies in
Vienna, Austria, and Lucerne, Switzerland, we examine AR applications
in planning participation and discuss the innovative nature of these
applications. We show that the use of AR not only increases the
motivation of the population to participate in planning processes but
also increases the quality of participation processes and can, thus,
trigger a sustainable transformation of cities.
Keywords
augmented reality, digital participation, impact on urban planning,
sustainable urban transitions, urban planning, virtual reality
55Frank Othengrafen, Lars Sievers, Eva Reinecke
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>
duce the physical city in a virtual world (Al-Kodmany 2002, Bill-
ger et al. 2017, Kikuchi et al. 2022, Rohil and Ashok 2022, Wilson
and Tewdwr-Jones 2022). As ongoing developments in numer-
ous European cities indicate, “[l]ocal governments [increasing-
ly] use 3D city models for urban planning and environmental
simulations such as estimating the shadows cast by buildings
[or] investigating how the noise from trac propagates through
a neighborhood” (Biljecki 2017, p. 3). Consequently, visualization
tools such as AR have become an essential platform for co-de-
signing with residents in urban spaces (Ruohomäki et al. 2018),
highlighting 3D visualizations of intended urban development
plans or projects contextually in physical spaces, and simulta-
neously, co-designing urban interventions in-situ (Lock et al.
2019).
However, existing studies and reports on AR tools and appli-
cations often refer to technical prerequisites, application possi-
bilities, etc. (e. g., Beneš et al. 2022, Boos et al. forthcoming, Höhl
and Broschart 2015), include cross-analyses of existing publica-
tions on AR (e. g., Rohil and Ashok 2022, Wolf et al. 2020), or
present AR applications with reference to specic topics (e. g.,
culture, tourism, transport planning) (Fegert et al. 2021, Kikuchi
et al. 2022). Thus far, only a few studies have focused on the use
of AR in urban planning processes (e. g., Saßmannshausen et al.
2021, Schürmann et al. 2021). This is the starting point for this
article, which considers the following research questions: How
is AR used in planning practice? For what purposes and in which
planning phases is it used? To what extent can AR contribute to
the sustainable transformation of cities, particularly with regard
to a more balanced participation of actors and to more transpar-
ent participation?
Augmented reality as both a digital visualization
and digital participation tool
We see AR as both a digital visualization tool and a digital partic-
ipation tool. AR was rst mentioned and dened by Caudell and
Mizell (1992, p. 660) as a technology which “is used to ‘augment’
the visual eld of the user with information necessary in the per-
formance of the current task”. This distinguishes AR from VR,
which can be described as “a computer-generated articial en-
vironment that makes the users of the device feel as if they are
in a dierent articial world” (Rohil and Ashok 2022, p. 1, see
also Schürmann et al. 2021). In contrast, in AR the representa-
tion of digital objects overlaps with reality, thereby implying that
actual situations are enriched with additional digital information
(Kikuchi et al. 2022, Zeile 2017). In this manner, for example, a
digital sketch of planned buildings, streets, or public spaces is
projected into the actual environment in real time (Zeile 2017,
p. 619, Rohil and Ashok 2022, p. 1).
According to Tomkins and Lange (2020, p. 372), AR oers a
novel tool for visualizing a wide variety of data. Thus, AR enables
planners, policymakers and other stakeholders such as citizens
to experience and better understand the intended changes in
the built environment and to identify potential conicts before
a development is implemented in practice. However, a review of
existing studies (Schürmann et al. 2021, Fegert et al. 2021, Beneš
et al. 2022, Wolf et al. 2020) reveals that AR applications have
often been used with regard to specic projects (e. g., a building
to be constructed, a street or park to be redesigned, etc.). In these
cases, it appears that AR is used when realizing a planned project
(but the project itself is no longer under discussion) for present-
ing variations in the design of the project (e. g., positioning of
furniture in a public space, etc.) to raise awareness and accep-
tance of the intended project. Here, AR – with its dierent levels
of detail (e. g., with regard to building cubature, façade design,
shading, etc.) – enables a rather realistic depiction of the intend-
ed structural-spatial development (Boos et al. forthcoming). How-
ever, whether or not AR applications are also suitable for the dis-
cussion on possible planning alternatives (e. g., for the intended
residential use of an inner-city browneld site) at the beginning
of strategic planning processes (where the outcome of planning
is still largely open) remains debatable.
Providing AR visualization in planning processes can increase
motivation and willingness to become involved in participatory
events, as AR systems provide new sources of information to sup-
port decision-making in the process (Boos et al. forthcoming,
p. 5). According to Tomkins and Lange (2020, p. 372), AR “open[s]
up new modes of communication and visualization to enhance
the widespread practice of model making and could be a exible
tool for designers, students, and stakeholders to analyze and com-
municate evolving or competing designs in a dynamic context”.
Therefore, AR visualizations oer manifold, often playful and
captivating, interactions with relevant stakeholders (Sankowska
2020). This is in line with the results of other studies (Saßmanns-
hausen et al. 2021, p. 252, Awang et al. 2020, pp. 53 .) that high-
light how AR can enhance motivational eects on stakeholders,
particularly on underrepresented groups such as young people,
thereby encouraging participation in planning processes via
gamication and other playful approaches.
Further, Awang et al. (2020, pp. 53 .) demonstrated that AR
applications as a basis for (digital) participation can increase the
willingness of stakeholders to participate in public planning pro-
cesses. They indicated that people prefer the use of 3D objects
and the 3D-visualisation of surroundings and building cubature
rather than 2D plans (Awang et al. 2020, pp. 54 f.). The selected
level of detail of the displayed objects in an AR application also
appears to make an impact on the users and, thus, inuence the
participation process. For example, an AR visualization with a
low level of detail could provide a less clear picture of a design,
thereby making it easier to engage the public in an early partic-
ipation process (Boos et al. forthcoming, p. 25). Furthermore,
more detailed visualizations can be used to provide a more con-
crete picture of a project in subsequent planning phases and
“could be used for purposes where authorities wish to make a
denitive commitment” (Boos et al. forthcoming, p. 25). How-
ever, there are very few studies that empirically analyze the ex-
tent to which AR can contribute to more eective and ecient
56 Frank Othengrafen, Lars Sievers, Eva Reinecke
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RESEARCH | SPECIAL ISSUE: SUSTAINABLE DIGITALIZATION
ways of public participation in planning processes – this relates
primarily to the role of initiating and participating actors, the
embedding of AR applications in planning processes, and the
presentation of planning content in AR presentations. There-
fore, the extent to which AR can “assist decision-makers, plan-
ners and communities to collectively plan and engage in creat-
ing sustainable, liveable and productive cities” remains unclear
(Lock et al. 2019, p. 1).
Research design and methodology
To be able to capture current AR applications in urban develop-
ment processes, we conducted an Internet-based desktop re-
search and literature analysis as well as a case study analysis of
two AR-based planning processes in practice. The literature re-
view concentrated on published articles in the Web of Science, Sci-
enceDirect, and Scopus databases. By using specic search terms
such as “3D visualisation”, “augmented reality”, “virtual reality”,
“digital participatory planning”, “virtual urban planning”, “virtu-
al urban reality”, and “digital twin”, we were, as a rst step, able
to identify relevant articles. In a second step, we read the ab-
stracts of the identied articles to allow a profound selection of
papers that, on the one hand, explain how AR applications work
and, on the other hand, have already made initial impact assess-
ments on the use of AR. Thereafter, we selected articles in which
the terms and concepts in the abstract strongly overlap with the
subject of our study (e. g., articles presenting case studies where
AR has been used for a sectoral planning process, etc.). Finally,
we selected 30 articles and analyzed them with the aim of de-
riving criteria for the analysis of the case studies in order to be
able to assess the potentials and weaknesses of AR in urban
development processes.
According to the literature analysis (see above), we derived
three research dimensions that are highly signicant for the use
of AR applications in practice but have not been researched ade-
quately thus far. This includes stakeholder constellations, trans-
parency, and the presentation of planning content. Stakeholder
constellations analyze the role of the actors who develop and use
AR applications (e. g., urban planning departments, start-ups,
research organizations) as well as interactions with potential us-
ers (other municipal departments, inhabitants, etc.). This must
also be considered in relation to transparency. Here, the follow-
ing aspects are highly relevant to understand the use and im-
pact of AR applications in the planning process: 1. the embedded-
ness of the AR application in the entire planning process (as well
as the integration with analog participation formats); 2. the plan-
ning phase or the point in time at which the AR application is
used in the planning process (rather open participation in an
early planning phase or rather limited participation in a subse-
quent participation phase); and 3. simple access to and use of the
application. The presentation of planning content includes the
depth of representation and the (visual) innovations that AR ap-
plications can bring to consultations in the planning process.
What is also of relevance here is which contents are visualized
in the application (and in what manner) and which are not, par-
ticularly with regard to sustainable development.
We then applied these dimensions in our case study analy-
sis. The identication of relevant case studies for the in-depth
analysis of AR applications followed a rather pragmatic research
approach, thereby implying that we searched for cases where we
could test AR applications in practice and where we could inter-
view the main actors regarding their experiences with the AR
applications. This included, among others, planners, app devel-
opers, and researchers. On this basis, we selected case studies in
Austria (Vienna), Germany (Hamburg, Karlsruhe), and Switzer-
land (Lucerne), where AR applications have recently been ap-
plied or are currently being tested in urban development pro-
cesses. The case study analysis includes guideline-based expert
interviews with involved municipal representatives, representa-
tives of AR companies, and researchers involved in developing
and implementing AR in the selected cities. Overall, we conduct-
ed nine interviews to identify the opportunities and challenges
of AR applications in urban planning processes. Five interviews
were linked to the two case studies in Vienna and Lucerne, which
are examined in greater detail in the following paragraphs. We
selected these two cases because the two AR tools developed
here relate to dierent application areas and dimensions and
have only recently been tested in practice. The interviews are
evaluated using qualitative content analysis in accordance with
Mayring (2015). In this context, the results of the interviews in
Vienna and Lucerne were also compared with the results of the
interviews from the other cities.
In both cases, the initiators of the AR applications also con-
ducted their own empirical surveys, the results of which were
available to us. These results, particularly those pertaining to us-
er groups and user satisfaction, provided further empirical nd-
ings that we used to assess the impact of AR in the two case
studies. In addition, the case study analysis consists of our own
experiences with the respective AR applications (particularly re-
garding issues such as functionality, degree of presentation –
what is presented and what is not –, susceptibility to interference,
and comprehensibility), which we were able to gain in the course
of self-tests of the AR tools on site. Further, we recorded and
evaluated our self-tests in accordance with the methodological
procedure for on-site visits. Based on the combination of the re-
sults from the expert interviews, the supplementary local sur-
veys and documents, and the self-tests, we then evaluate the case
studies before we nally discuss and evaluate the overall poten-
tials and weaknesses of AR applications in planning processes.
Making climate eects visible via augmented
reality – Bernardgasse in Vienna
The rst case study is an AR application for the redesign of
Bernardgasse in Vienna, Austria. The water pipes in Bernard-
gasse require renewal and, thus, the district authority is taking
57Frank Othengrafen, Lars Sievers, Eva Reinecke
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>
the opportunity to redesign the entire street with an eye to the
future. Currently, the one-way street is characterized by histor-
ical residential block perimeter development (gure 1).
The street is a single lane one, the sidewalks are narrow, and
parked cars make it crowded, so there is little space left for pub-
lic use. Bernardgasse is barely landscaped, thereby making it
rather warm in the summer (GLARA Forschungskonsortium et
al. 2021, pp. 5 f.). The city has already developed initial concepts
to make the street more climate-friendly and sustainable through
green structures. To illustrate the impact of greening on temper-
atures, an initial participation process with various analog events
and an AR application was initiated in a comparatively early plan-
ning phase between October 14 and November 7, 2021. The tar-
get group for participation was the immediate neighborhood
with residents of Bernardgasse and adjacent side streets. The AR
application was developed and tested as part of the GLARA re-
search project1, a consortium comprising dierent partners such
as the seventh Vienna municipal district, architecture and land-
scape architecture companies (superwien urbanism ZT GmbH
and Green4Cities GmbH), a company specializing in the devel-
opment of digital visualization tools (Fluxguide Ausstellungs-
systeme GmbH), and an international competence center for
urban green infrastructures (tatwort Nachhaltige Projekte GmbH)
(stakeholder constellation).
The participation was organized by the GLARA project con-
sortium and implemented by using dierent (analog and digi-
tal) methods, which included a “kick-o event”, “information
points”, the “GLARA app”, and a “survey” (GLARA Forschungs-
konsortium et al. 2021, pp. 10 – 13). The transparent participation
process began with an on-site kick-o event on October 14, 2021.
The event was attended by approximately 80 residents, who were
involved through “emotional mapping” to communicate their
wishes and ideas on the topics of 1. microclimate, 2. quality of
stay, 3. trac and street space (GLARA Forschungskonsortium
et al. 2021, p. 10). In addition, their wishes and requirements for
the redesigning of the street were considered in small groups.
Subsequently, information points were set up along Bernard-
FIGURE 1: Visualization of heat stress, that is, temperatures in Bernardgasse, Vienna, AT, in order to sensitize residents to climate-adapted urban
development. Source: www.uxguide.com/puls/glara-kick-o-in-der-bernardgasse.
1 The GLARA research project (Green Living Augmented + Virtual Reality) aims
to create a low-threshold participatory planning process that enables and
supports the design of green spaces with the participation of all stake-
holders. Therefore, GLARA develops various analogue and digital participa-
tion formats in order to activate dierent stakeholders. These formats and
tools are currently being used and tested in two case studies in Vienna for
the redesign of public spaces (Green4Cities GmbH 2022).
© Fluxguide/GLARA
58 Frank Othengrafen, Lars Sievers, Eva Reinecke
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RESEARCH | SPECIAL ISSUE: SUSTAINABLE DIGITALIZATION
gasse between October 18 and October 22, 2021 (GLARA For-
schungskonsortium et al. 2021, p. 12). A total of 90 participants
took advantage of this opportunity and contributed additional
ideas to the process.
At the same time as the kick-o event, the GLARA app was
released – an AR application that enabled the public to digitally
experience the climatic impacts and eects of urban planning
measures for sustainable urban development on hot summer
days as well as the actual state of the microclimate in Bernard-
gasse during the participation phase (GLARA Forschungskon-
sortium et al. 2021, p. 13). The app was linked to the survey on
the redesign of Bernardgasse, thereby providing participants the
opportunity to comment digitally on the process and intended
planning options in the period from October 14 to November 7,
2021. Further, individuals could participate in the survey not on-
ly via the GLARA app but also via a desktop application, and in
print format. A total of 172 people completed the survey (GLARA
Forschungskonsortium et al. 2021, p. 13).2 Of the 164 respons-
es3, the age group of 30 to 44 years was dominant, accounting
for 45 % of the participants. This was followed by those aged 45
to 59 years, accounting for 23 % of the participants. In addition,
those aged between 20 to 29 years accounted for 17 % of the par-
ticipants and those aged 60 years or over accounted for 13 % of
the participants. It is striking that the group of younger people
(19 or younger) is clearly underrepresented in the participation
process, accounting for only 2 % of the participants (GLARA For-
schungskonsortium et al. 2021, p. 15).
The GLARA app was the essential tool for conducting digi-
tal participation via AR (gure 2). It was publicly accessible and
can be downloaded from the Google Play Store (Android) or the
Apple App Store (iOS) to be installed on private devices (smart-
phones or tablets). However, no smartphones or tablets were
provided to the public, which is considered a hurdle for an open
participation process, as people without a terminal device and
older groups of people may, therefore, have found it dicult to
participate. It was also observed that the functionality of the ap-
plication cannot be guaranteed on all smartphone models. The
positioning of the AR display employed marker-based access,
where users scanned a QR code in the form of a street sticker
to calibrate the visualization. This calibration was intuitive and
caused no technical problems in the self-test conducted by the
authors – by focusing on the marker with the tablet camera, the
calibration was completed within a few seconds.
In the AR application, urban planning options are displayed
in dierent variants and scenarios with reference to the climat-
ic situation in Bernardgasse (presentation of planning content).
Beginning from a status quo with current climate data, variables
that simulate dierent scenarios of structural or open space
planning interventions can be selected (e. g., various forms and
intensities of greening, reduction of parking places) and their
microclimatic eects can be witnessed (gure 3). A setting for
dierent times of day or night and scenarios regarding the po-
sition of the sun is also enabled in the GLARA app. This makes
it possible for the public to experience the eects of urban plan-
ning measures related to climate adaptation and their impact
on the (perceived) temperature (in °C) in Bernardgasse (but the
participants cannot develop their own drafts or planning op-
tions). Thus, the representations of climate data in augmented
reality illustrates the eect of specic climate adaptation and
mitigation measures. Through this, the eects of the planning
interventions on the microclimate can immediately be experi-
enced and the understanding of specic approaches to climate-
adapted and sustainable urban development is promoted (as part
of the knowledge transfer). All participants were able to evaluate
concrete interventions from the same perspective.
Overall, a transparent approach to citizen participation is evi-
dent in the rst participation phase for the redesign of Bernard-
gasse in line with sustainable urban development. In public par-
2 Of the 172 participants in the survey, 135 people participated via
web browsers, nine used the printed form, and 28 participated via the
GLARA app (GLARA Forschungskonsortium et al. 2021, p. 14). This
indicates that it was possible, in a short period of two weeks, to introduce
the AR application and to actively use it in the planning process.
Simultaneously, it becomes evident that other participation formats
have a longer range thus far, thereby implying that AR applications
should be linked with other participation tools.
3 Of 174 participants in the survey, 164 persons answered this question.
FIGURE 3: Visualization of temperature dierences with and without
planting in Bernardgasse, Vienna, AT, using augmented reality.
Source: www.uxguide.com/puls/glara-kick-o-in-der-bernardgasse.
FIGURE 2: Access to and use of an augmented reality (AR) application in Vienna, AT (schematic diagram).
© Fluxguide/GLARA
59Frank Othengrafen, Lars Sievers, Eva Reinecke
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SPECIAL ISSUE: SUSTAINABLE DIGITALIZATION | RESEARCH
ticipation, both analog and digital formats are introduced in the
participation process, both of which can complement each oth-
er in a meaningful manner. The entire participation phase was
stringently organized and communicated to the residents via a
kick-o event, yers, and visibility in the public space through
various information points. Thus, the GLARA app strongly sup-
ported the participation process and the transfer of knowledge
of climate data to the population via the simulation of microcli-
matic eects. Moreover, within the GLARA app, there were op-
portunities for the public to participate in the survey on the par-
ticipation process in order to comment on the intended plans
and options. Overall, the participation process in Vienna is char-
acterized by a combination of dierent approaches, both analog
and digital, which complemented each other. This makes the
overall participation process broader, with the aim of respond-
ing better to the disadvantages of classic formats and enabling
the involvement of multilayered population groups.
Making future street design visible via
augmented reality – Bahnhofstrasse and
Theaterplatz in Lucerne
The case study in Lucerne, Switzerland, was a research project
in cooperation with the Civil Engineering Oce of the city of
Lu cerne and the research groups Visual Narrative and Immersive
Realities Research Lab of the Lucerne University of Applied Sci-
ences and Arts. The aim was to free Bahnhofstrasse and Theater-
platz from motorized trac, to redesign the public space (plant-
ing 30 new trees, etc.) and to upgrade the street with an under-
ground bicycle station that also provides a direct connection to
the main station (which was rejected in a referendum in Febru-
ary 2022) (City of Lucerne 2022). Due to its location in the city
center, the public interest in this project is comparatively high.
The aim of the AR-based participation process in September 2021
was to make the various options and solutions accessible to the
broad public during the planning process and to communicate
with them in a transparent and comprehensible manner (Schür-
mann et al. 2021, p. 43).
The rst plans and concepts for the redesign of Bahnhof-
strasse were already developed in 2014. In 2016, an urban plan-
ning competition took place, in which various planning options
for the designated area were presented. On this basis, the Civil
Engineering Oce developed the nal plan, which was then
presented to the public in September 2021 as part of the formal
planning process (City of Lucerne 2022). During the prelimi-
nary considerations for the pending participation process in ear-
ly summer of 2021, a private meeting took place between mem-
bers of the Civil Engineering Oce and the University of Applied
Sciences and Arts Lucerne (on the initiative of a leading admin-
istrative manager of the Civil Engineering Oce). By analyzing
the stakeholder constellation, two aspects became decisive ones
for the city administration to become involved in such a partici-
pation format. First, the open and uncomplicated attitude of in-
dividual members of the Civil Engineering Oce. Their focus
was on testing new technologies like AR and to see if they could
oer benets for public participation processes (the risk of fail-
ure was accepted). Second, the “strategy for shaping digital
change in the economy, society, and public administration” of
the Canton of Lucerne, which at least established the founda-
tion for innovative and digital participation formats in the city of
Lucerne. This gave rise to the idea of using an AR application to
support the participation process and to present the intended
planning in a more comprehensible and understandable man-
ner. The use of AR at this comparatively late stage of the plan-
ning process was to present the selected planning alternative
and obtain citizens‘ approval for it before the city council could
subsequently decide on and implement this alternative (gure 4,
p. 60). The discussion of other ideas or alternatives via AR was
not foreseen at this stage.
After the public was informed through various media such as
the newspaper, the internet and posters in public spaces, citizens
were able to participate in guided tours of Bahnhofstrasse with
the help of AR in September 2021 (transparent participation pro-
cess). The target group for the participation process included peo-
ple aected by the plans and local citizens, politicians, and oth-
er interested parties. People of dierent ages from these groups
were involved during the guided tours; this made it evident that
younger people, in particular, could be motivated to participate
at the guided tours through the AR-based participation. Almost
28 % of the participants were between 18 and 35 years old, 60 %
of the participants were between 36 and 55 years old, and 12 %
were over 56 years old (Schürmann et al. 2021, p. 47). However,
compared to analog participation formats, the overall number
of participants was not more culturally or socially heterogeneous.
Further, in order to be able to use the AR application, guided
tours were oered by the project partners (transparent participa-
tion process). On these tours, participants were provided with tab-
lets and could use the mobile devices to virtually view new de-
sign elements like seating, bike racks, and plantings as 3D vis-
ualizations in the public space (Lucerne UAS 2021). As the pro-
ject partners were in favor of simple and low-threshold access,
the AR application was installed on these tablets; there was no
need to download apps or register with personal data to use the
application (gure 5, p. 60). In case of technical questions or prob-
lems, members from Lucerne University of Applied Sciences
and Arts or the Lucerne Civil Engineering Oce were available
on site. The only step that the participants had to take in order to
be able to see the AR representation with positional precision
was to calibrate it to pre-dened markers (viewpoints). Switch-
ing between dierent views within the application also involved
no time delay. Further, viewing dierent variants from dierent
perspectives formed the heart of the AR application. Within the
application, there were technical options that enabled partici-
pants to make a note of their own opinions verbally or in writ-
ing and to create their own designs. Overall, the AR application
was positively evaluated by the participants in a non-represent-
ative survey conducted by the organizers in Lucerne; moreover, >
60 Frank Othengrafen, Lars Sievers, Eva Reinecke
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RESEARCH | SPECIAL ISSUE: SUSTAINABLE DIGITALIZATION
there were no complaints regarding the technical application
(Schürmann et al. 2021, pp. 47 – 48).
In the AR application, the redesign of Bahnhofstrasse and
Theaterplatz is visualized by displaying the locations of objects,
such as trees, seating, and bicycle stands (presentation of planning
content). The participants can switch between dierent display
types or variants in the view. The level of detail is very high and,
thus, the representation of the individual objects is rather de-
tailed. Even the shadows are visible, thereby making the virtual
objects appear even more real. Further, there is no setting for
dierent times of day or night or weather scenarios, which could
have enabled planning designs to be visualized in dierent light-
ing situations (gure 6). Nonetheless, a fusion between reality
and virtuality is enabled on mobile devices. Only little negative
feedback was received for participation exercises using AR appli-
cations as compared to that for analog participation exercises
without digital technology. Analog participation formats often
present 2D plans or renderings that participants need to under-
stand despite lacking planning knowledge. Such images may be
interpreted in dierent ways. However, the AR applications en-
abled discussions between dierent stakeholders about the plan-
ning content and were factual, as everyone had the same per-
spective on the plans or digital perspectives, thereby implying
that the intended planning options were transparent for all. Thus,
the representations in AR objectied the discussions among the
various stakeholders. Further, unsubstantiated claims and com-
plaints regarding planning situations, which are often otherwise
made in participation processes, played no role here. All stake-
holders were able to discuss concrete issues on the same basis,
which resulted in dynamic discussions.
Overall, the participation in the redesign of Bahnhofstrasse
and Theaterplatz in Lucerne can be considered a good example
of participation in urban planning with the help of AR. Accord-
ing to a survey on the participation format (Schürmann et al.
2021, p. 47), the combination of using the AR application as well
as having the plans and posters simultaneously available in print-
ed form was preferred by most participants. The AR application
is intuitive and easy to use. Moreover, the technology works with-
out interference. The planning content is mapped transparent-
ly and has, thus, contributed to the success of the participation
process as the technology supported face-to-face discussion of
FIGURE 4: Redesign of Bahnhofstrasse, Lucerne, CH: virtual objects such as the new line of trees and seating are projected into the actual environ-
ment. Source: https://www.hslu.ch/de-ch/hochschule-luzern/ueber-uns/medien/medienmitteilungen/2021/08/19/ar-umgebung-bahnhofstrasse, modied.
FIGURE 5: Access to and use of an augmented reality (AR) application in
Lucerne, CH (schematic diagram).
© Lucerne UAS 2021
61Frank Othengrafen, Lars Sievers, Eva Reinecke
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the planning content not only among the participants but also
with members from the Civil Engineering Oce. However, the
guided tours also “excluded” people who could not attend on the
dates on which the tours took place. If the AR application had
been made available on tablets and private smartphones, people
would have been able to participate at any time. Furthermore, it
would be helpful to integrate a participation tool into the appli-
cation that not only enabled viewing but also created a collection
of opinions to identify further ideas for implementation. In gen-
eral, the AR application was used at a comparatively late stage
in the formal planning process and was exclusively concerned
with concrete design issues. However, the planning alternative
itself was not up for debate due to the formal and advanced plan-
ning process.
Conclusion
The case studies in Vienna and Lucerne reveal that using AR
not only increases inhabitants’ motivation to participate in plan-
ning processes but can also contribute to improving the quality
of participation processes. The AR applications in Vienna and
Lucerne present the planning intentions in a more realistic man-
ner, as the concrete projects (planting of trees, creation of a cy-
cling connection, installation of benches, etc.) are displayed in
front of the actual existing background appearance. However, the
extent to which AR-based visualizations – with their high level
of detail, simulations, etc. – are actually better suited for partic-
ipation processes than 2D plans (e. g., in the form of increased
participation, more intensive discussions) was not directly ana-
lyzed in the two case studies and has not been addressed in the
subsequent surveys by the project partners in Vienna and Lu-
cerne. Nevertheless, experiences from other studies and research
projects suggest that AR applications can signicantly improve
the quality of the participation process (see above research de-
sign).
AR applications can also be used in dierent planning phas-
es. In Vienna, AR was used at the very beginning of the planning
process. By presenting scenarios and options for action via AR,
the intention here was to raise awareness for planning actions
that might help to improve the microclimate. Here, AR is partic-
ularly benecial as various, and occasionally conicting, alter-
natives and solutions can be discussed and compared. In Lu-
cerne, AR was used at the end of the planning process. Here, the
city of Lucerne used an AR application to present the selected
planning option on site (including the intended design of the
public space); however, there was no discussion of the planning
alternative in the AR application. Other studies and research >
FIGURE 6: Plants and seating can be displayed as one of three variants (A, B, C), along with shading options and a playground, as virtual objects
in real space in Bahnhofstrasse, Lucerne, CH, using augmented reality. Source:
https://www.hslu.ch/de-ch/hochschule-luzern/ueber-uns/medien/medienmitteilungen/2021/08/19/ar-umgebung-bahnhofstrasse, modied.
© Lucerne UAS 2021
62 Frank Othengrafen, Lars Sievers, Eva Reinecke
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RESEARCH | SPECIAL ISSUE: SUSTAINABLE DIGITALIZATION
projects (see research design above) similarly indicate that AR is
mainly used in specic planning phases – primarily in advanced
stages in the planning process – in order to visualize and, if nec-
essary, objectify issues. Thus, the potential of AR applications
in planning may not fully be exploited; therefore, in the future,
the aim should be to use AR across all planning phases to vis-
ualize possible implications of individual projects in early plan-
ning phases and to make the discussion on planning alterna-
tives more interactive and transparent.
Further, the case studies in Vienna and Lucerne and Vienna
reveal that the dierent forms of visualization in the AR appli-
cations in Vienna and Lucerne contributed to making planning
more tangible for participants. The experiences indicate that the
use of AR applications, compared to analog participation for-
mats and 2-D representations, helps to prepare the planning in-
formation for all interested parties in a visual and descriptive
manner. Simultaneously, it makes the planning options more
transparent, thereby implying that the AR application makes dis-
cussions among planners, politicians, citizens, and other stake-
holders more objective. The Lucerne case study has shown that
AR can also motivate groups that have been thus far underrep-
resented to participate in planning processes. However, the ex-
periences in Vienna also indicate that the acceptance of AR as a
visualization and participation tool has, thus far, been rather low
compared to analog participation formats. Additionally, it was
evident that AR as a digital participatory tool is not available to
all users and, thus, there may be dierences in accessibility and
usage. Here, it must be ensured that participation processes based
on AR do not lead to a manifestation of social inequalities. The
combination of analog and digital participation tools may make
sense here, but reliable results on this are not yet available. In
any case, further research is needed in this respect, as the sur-
veys conducted thus far tend to refer to user satisfaction with the
AR application; the quality of the visualizations or the incorpo-
rating of the results in the further planning process has not yet
been researched.
Nevertheless, AR applications can help ensure that sustain-
able development goals are given more importance in planning
processes by, for example, displaying simulations relevant to ur-
ban sustainable transitions and testing scenarios or fostering in-
teractive decision-support systems (Potts 2020, 283). This is rath-
er evident in Vienna, where the AR application depicts the con-
sequences of climate change for the urban neighborhood and,
simultaneously, allows the selection of specic planning options
(particularly planting measures) to learn how these options might
improve the microclimate. By doing so, the AR application con-
tributes to a sustainable planning process and, consequently, to
sustainable urban development, because planning contents are
presented in a real and transparent manner before actual con-
struction measures begin.
In addition, AR applications also oer the potential to be
linked with articial intelligence (AI) systems.4 New technical
solutions in computer graphics, data mining and visualization,
and visual and statistical analyses (Kitchin 2022, pp. 100 f.) enable
urban planners and decision-makers “to tie these visual tools in
with much more detailed, longitudinal, massive performance
data sets to support comprehensive and useful forms of visual
analytics” (Lock et al. 2019). For example, with regard to climate
mitigation and adaptation, a digital twin (Dembski et al. 2020,
Ruohomäki et al. 2018) could represent the digital (cross-section-
al) infrastructure of the climate-neutral city and also integrate
georeferenced data, real-time data (e. g., trac ows, energy con-
sumption), etc. On this basis, AR can be used to develop “what
happens if …” scenarios to illustrate, for example, the impact or
eectiveness of individual options (e. g., shifts in trac ows,
energy savings in the neighborhood) with regard to climate pro-
tection or adaptation goals. In this vein, digital twins (as part of
AI) and AR can together contribute to facilitating coordination
of climate mitigation and adaptation options of dierent munic-
ipal departments. Simultaneously, they can analyze and evaluate
sustainable and less sustainable development options through-
out the entire planning process (from the development of alter-
natives to the concretization of partial solutions to design issues
at the building level). Additionally, they can contribute to in-
creasing the transparency and acceptance of climate mitigation
and adaptation options among private actors and to improve the
decision-making basis for politicians and planners. However, fur-
ther empirical research and studies must be conducted in this
regard, as all AR applications thus far have been developed and
tested in research projects with a limited duration, thereby im-
plying that they have not been actualized in a comprehensive,
longer-term manner.
Acknowledgement:We would like to thank three anonymous reviewers for
their helpful comments.
Funding: The article was written as part of the research project 5G-CityVisAR
(funding code: 005-2108-0048), which is supported and funded by the
Ministry of Economic Aairs, Climate Protection and Energy of the State of
North Rhine-Westphalia as part of the 5G.NRW funding competition.
Competing interests: The authors declare no competing interests.
Author contribution: All authors were involved in the initial research,
conceptualization, manuscript writing and nal approval. L. S. takes
responsibility as corresponding author.
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Lars Sievers
Studies in spatial planning (BSc/MSc) at TU Dortmund Uni-
versity, DE. Since September 2019 research assistant at the
faculty of spatial planning, department Urban and Spatial
Planning, TU Dortmund University. Research interests: digi-
talization, urban planning, neighborhood development, im-
mission control and noise protection.
Eva Reinecke
Studies in geography (BA) at Ruhr-University Bochum, DE,
and spatial planning (BSc/MSc) at TU Dortmund University,
DE, and Università degli studi di Bergamo, IT. Since Decem-
ber 2021 research assistant at the faculty of spatial planning,
department Urban and Spatial Planning, TU Dortmund Uni-
versity. Research interests: digital participation in urban de-
vel opment, smart cities, neighborhood development.
Frank Othengrafen
Studies in spatial planning (Dipl.-Ing.) at TU Dortmund Uni-
versity, DE. 2010 Dr.-Ing. (HafenCity Universität Hamburg,
DE). Since April 2019 head of research group at the faculty of
spatial planning, department Urban and Spatial Planning, TU
Dortmund University. Research interests: planning practices,
planning cultures, digitalization of participation, sustainable
transformation of urban regions.
