Accessible Web Maps for Visually Impaired Users: Recommendations and Example Solutions

Abstract

Due to advances in information and communication technology, web maps are an increasingly important means of communication. While paper maps provide solutions that are accessible to the visually impaired, the use of web maps is still difficult for these users. This is true even though technology opens up new possibilities for developing accessible web maps. But, what must be considered when creating web maps suitable for the visually impaired? This paper presents recommendations including example solutions based on the results obtained in two projects: AccessibleMap and senTour. In both projects mixed methods were used: literature and Internet review, questionnaires, and analysis of similar systems. All work was done in close cooperation with organizations that represent the interests of the target group.
The findings underline that web maps accessible to visually impaired users must support different interaction modes and assistive technology. A carefully designed user interface, an easy-to-read map picture, and the provision of a verbal description of the map content are important. Further, additional aspects should be considered to enable these users to fully benefit from web maps. This refers to the need to widen concept of accessibility, encompassing among others usability, the importance of building up these users’ digital and spatial competencies, and to leverage the advantages that result from the application of the participatory design approach.

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Accessible Web Maps for Visually Impaired Users – Hennig et al. | 5
Sabine Hennig
Paris Lodron University of Salzburg
sabine.hennig@sbg.ac.at
Fritz Zobl
Paris Lodron University of Salzburg
fritz.zobl@sbg.ac.at
Wolfgang W. Wasserburger
AccessibleMap Association/TU Wien
wolfgang@wasserburger.at
Accessible Web Maps for Visually Impaired Users:
Recommendations and Example Solutions
Due to advances in information and communication technology, web maps are an increasingly important means of com-
munication. While paper maps provide solutions that are accessible to the visually impaired, the use of web maps is still
difficult for these users. is is true even though technology opens up new possibilities for developing accessible web maps.
But, what must be considered when creating web maps suitable for the visually impaired? is paper presents recommen-
dations including example solutions based on the results obtained in two projects: AccessibleMap and senTour. In both
projects mixed methods were used: literature and internet review, questionnaires, and analysis of similar systems. All
work was done in close cooperation with organizations that represent the interests of the target group.
e findings underline that web maps accessible to visually impaired users must support different interaction modes and
assistive technology. A carefully designed user interface, an easy-to-read map picture, and the provision of a verbal de-
scription of the map content are important. Further, additional aspects should be considered to enable these users to fully
benefit from web maps. is refers to the need to widen the concept of accessibility, encompassing among others usability,
the importance of building up these users’ digital and spatial competencies, and to leverage the advantages that result from
the application of the participatory design approach.
KEYWORDS: accessible maps; accessibility; usability; web maps; visually impaired users; disabled users; special needs
users; digital and spatial literacy; participation
INTRODUCTION AND RESEARCH QUESTIONS
F  C (1995) suggest that maps are perhaps
as fundamental to society as language and the written
word. ey help people to orient themselves in physical
space, to navigate from place to place, to plan routes, to ac-
quire spatial knowledge, and to build up cognitive or men-
tal maps (Helal et al. 2004; Montello and Freundschuh
2005). For persons who are blind, or who are severely vi-
sually impaired, maps are even more important. Without
a visual sense, they can easily lose their orientation, partic-
ularly when traveling in unknown environments (Clark-
Carter et al. 1986; Helal et al. 2004). Maps enable them to
construct a cognitive map of as yet unknown areas, which
they can later recall from memory while on-site, support-
ing them in independently finding their way (Brock et al.
2013; Golledge et al. 1996).
Web maps, like many other technologies, have the po-
tential to enhance the quality of life and independence of
disabled people (Harris 2010; WHO 2007). Nevertheless,
technology does not automatically bring them benefits
merely by existing (Macdonald and Clayton 2013): solu-
tions must be implemented with an understanding of a
user group’s requirements. However, while web maps have
the potential to benefit persons who are visually impaired,
current examples rarely meet the requirements of this user
group. Depending on the type and degree of a user’s visu-
al impairment, web maps can be quite challenging; in the
case of people who are severely visually impaired or blind,
their use is often hardly possible at all (Call-Jimenz and
Lujan-Mora 2016; Höckner et al. 2012; Zeng and Weber
2011). Barriers that generally hinder these users from using
DO I : 10.14714/CP88.1391 PEER-REVIEWED ARTICLE

Cartographic Perspectives, FORTHCOMING Accessible Web Maps for Visually Impaired Users – Hennig et al. | 6
web maps have been discussed by other authors (see, for
example, Calle-Jimenez and Lujan-Mora 2016; Höckner
et al. 2012): they may be too complex to use, feature inap-
propriate graphical design of the user interface and/or the
map, suffer from a lack of appropriate interaction modes,
or lack a verbal description of the map content.
To support the creation of web maps that are accessible
to visually impaired users, several open questions need
to be answered: What guidelines exist to support their
development? Which applications already exist that can
serve as examples to guide the design and implementation
of accessible web maps? What recommendations can be
offered to support the development of web maps accessible
to visually impaired users? Which additional approach-
es, beyond a consideration of accessibility, can support
the creation and use of such web maps? e findings we
discuss in this paper are based on knowledge gained from
two projects: AccessibleMap and senTour.
BACKGROUND
TARGET GROUP
T  “ ” covers a wide range
of different types and degrees of eye disorders and vi-
sion loss. As described by the International Council of
Ophthalmology (2002), this encompasses minimal impair-
ments; mild, moderate, severe, and profound vision loss;
near-blindness and blindness; as well as color vision loss
(Table 1). According to the World Health Organization
(2013), in 2011 the number of people with reduced vision
and blindness amounted to approximately 285 million
worldwide, with 246 million suffering from low vision and
39 million affected by blindness. The reasons for visual
impairment are manifold: examples include uncorrected
refractive errors, cataracts, glaucoma, diabetic retinopathy,
trachoma, corneal opacities, and age-related macular de-
generation (Pascolini and Mariotti 2012).
Due to increasing life expectancies, the number of older
persons is on the rise in many parts of the world. e over-
65 population proportion is expected to more than dou-
ble globally over the next forty years, climbing from 7% to
16% (to nearly 1.5 billion people). As the older population
increases, so will the number of people affected by visual
Ranges of vision loss Ability, ranges Reading ability
(Near-)
Normal
Vision
Range of normal
vision Normal
Normal reading speed
Normal reading distance
Reserve capacity for small print
Minimal impairment
Almost normal
Normal reading speed
Reduced reading distance
No reserve for small print
Mild vision loss
Low vision
(partially
sighted)
Moderate vision loss Normal with aids
Near-normal
Appropriate reading aids: strong reading glasses, large print books,
readers, audio taped texts, and raised-line drawings
Severe vision loss Restricted with aids
Slower than normal
Require reading aids
High power magniers
Profound vision loss Marginal with aids Visual reading is limited
Magniers for spot reading, talking books
(Near-)
blindness
Near-blindness
(legal blindness) (Near-)
impossible No visual reading: talking books, Braille or other non-visual sources
Total blindness
Table 1. Types and degrees of visual impairment (CUDE 2015; ICO 2002; WHO 2013).

Cartographic Perspectives, FORTHCOMING Accessible Web Maps for Visually Impaired Users – Hennig et al. | 7
impairment—age is a significant factor in the decline of
vision capacity. is is emphasized by the following num-
bers: while approximately 20% of the world’s population
is age 50 and older, about 65% of all visually impaired
people worldwide belong to this age group (Pascolini and
Mariotti 2012; WHO 2013).
Another significant population that must be considered
are those persons with color vision impairments. is term
refers to an inability to distinguish certain color shades,
or, in more severe cases, to see colors at all (AOA 2014).
While many different forms of color vision impairments
exist, the most common are: (1) protanopia (reduced sensi-
tivity to red light), (2) deuteranopia (reduced sensitivity to
green light), and (3) tritanoptia (blue-yellow color blind-
ness). is trait is mainly carried by a sex-linked genetic
disorder (though it can also be caused by injury, disease,
or medication side effects); approximately 8% of the total
male population and 1% of the total female population
suffer from color vision deficiency (AOA 2014; Culp 2012;
Olson and Brewer 1997). Since mapmakers often use col-
ors to represent different categories of map features and to
facilitate visual grouping, users suffering color visual im-
pairment can find reading maps challenging—especially if
maps are produced with little or no consideration for them
(Olson and Brewer 1997).
RELATED WORK
Accessibility-oriented products aim to improve the extent
to which everyone in a society is able to live independent-
ly and self-determinedly, and to participate fully in all as-
pects of life (ITU/G3ict 2014b). is is done through a
focus on ensuring an equivalent user experience for peo-
ple with disabilities (W3C 2010). As the internet becomes
more and more a part of daily life for many people, numer-
ous initiatives on web accessibility have emerged in recent
years. eir focus is on the removal of technical barriers
that hamper access to information, with the aim that all
people can perceive, understand, and operate every con-
trol, instruction, or output related to a website (ITU/G3ict
2014b; W3C 2005; W3C 2012).
Like other accessible products, maps tailored to the needs
of visually impaired people are not new. High contrast
maps, large font maps, tactile maps, and Braille maps are
well-established analog products. Technological advanc-
es—especially since the mid-1990s—have also facilitated
the development of a variety of digital maps supporting vi-
sually impaired users. Examples include
• virtual acoustic maps representing information about
features such as lakes, parks, and streets as verbal and
non-verbal audio output (Heuten et al. 2007; Zhao et
al. 2005);
• virtual tactile maps, in which tactile displays and
other haptic devices (such as a joystick or haptic
mouse) are used to explore maps (Moustakas et al.
2007; Parente and Bishop 2003);
• tactile-audio maps, in which users explore maps with
their fingers using touch-sensitive pads and obtain
more detailed information from auditory representa-
tions (Wang et al. 2009); and
• Braille tactile maps, which use tactile and touch-en-
abled Braille displays to present map information
(e.g., points of interest) as well as interaction functions
(pan, zoom, search, etc.) through raised pins (Zeng
and Weber 2010).
As they have become more popular in recent years (and
featured greater capabilities), a number of researchers have
also worked to develop interactive web maps tailored to vi-
sually impaired users (see, for example, Brock and Jouffrais
2015; Helal et al. 2004; Poppinga et al. 2011; Rener 2017;
Sánchez and Torre 2010; Siekierska and McCurdy 2008).
PROJECTS AND METHODS
T    in this paper
rely on work conducted in two projects: AccessibleMap
and senTour. Both projects aimed at implementing a web
map pilot suitable for the disabled, and especially for peo-
ple who are visually impaired (Table 2).
A good understanding of the user groups and their needs
played a key role in both projects, and thus was a focus
of much of our effort. e workflow and methods used to
gain this knowledge about visually impaired users were
quite similar for each project (Figure 1), and included
literature reviews, questionnaires, internet research, and
analysis of similar systems (AoSS). roughout the en-
tire development process we also cooperated closely with
stakeholders (i.e., organizations that represent the inter-
ests of the target group). e results of these efforts were

Cartographic Perspectives, FORTHCOMING Accessible Web Maps for Visually Impaired Users – Hennig et al. | 8
then combined and allowed us to develop design recom-
mendations. Additionally, the findings obtained in the
AccessibleMap project provided background for the sub-
sequent senTour project.
Literature Review
In the first step, existing information on what to consider
when creating web maps for visually impaired users was
collected through a literature review. Our focus was on lit-
erature regarding (web) accessibility, geoinformatics and
cartography, software and web engineering, and behavior-
al geography.
Questionnaires
In both projects questionnaires, prepared using the in-
ternet survey tool SurveyMonkey, were used to close
AccessibleMap project senTour project
Duration 2011–2013 2014 – 2016
Funding Austrian Federal Ministry of Transport, Innovation and Technology (BMVIT) under the FFG Benet Program
Goal
Development of a web map pilot that allows users
to explore and memorize a city area and/or a route
before going there
Development of a web portal, including an accessible
web map that informs users of (accessible) recreational
infrastructure (parking, trails, points of interest, etc.)
(Main) target group The visually impaired, including the blind and color
vision impaired
The disabled and elderly with focus on visually
impaired users (due to the relevance of age-related
vision changes)
Study area An urban environment: the 2nd and 20th districts of
Vienna A natural site: Austria’s Gesäuse National Park
Table 2. Overview of the AccessibleMap and senTour projects.
Figure 1. Workow and methods used in the AccessibleMap and senTour projects to gain understanding of users and their needs and to
develop design recommendations.

Cartographic Perspectives, FORTHCOMING Accessible Web Maps for Visually Impaired Users – Hennig et al. | 9
knowledge gaps identified through the literature review.
The AccessibleMap project questionnaire—addressing
visually impaired and blind users—consisted of 55 open
and closed questions (Table 3): 20 questions were directed
towards all users, 16 towards profoundly visually impaired
and blind users, and 19 towards users with low vision in-
cluding color vision impairments. Several questions were
asked in order to collect information about which existing
city web maps the target group used and which aspects
and features they liked and disliked about these applica-
tions. e questionnaire was distributed through face-to-
face interviews and via email in the autumn and winter of
2011–12, in Austria, Germany, and Switzerland.
e senTour project used two questionnaires. e first was
addressed to managers of large protected areas in Germany,
Austria, and Switzerland in the autumn and winter of
2014–15. It encompassed 17 mostly open questions focus-
ing on their experience with (digital/web-based) accessible
products and which solutions they considered to be exam-
ples of best practices. e second questionnaire was direct-
ed towards the target user group. It contained 23 open and
closed questions on socio-demographic data (e.g., place of
residence, age, gender, educational level), the infrastruc-
ture used and desired by the target group, sources of infor-
mation available for them to plan and conduct recreational
visits to natural sites, and their preferences regarding the
provision of information (amount, type, etc.). In the spring
of 2015, the questionnaire was distributed through email;
face-to-face interviews were also conducted.
Internet Research and AoSS
We then conducted an analysis of similar systems (Nemeth
2004) based on the applications and elements mentioned
by the questionnaire respondents as well as those iden-
tified through internet research. Attention was given to
aspects such as user interface and map design, the content
and functionalities implemented, and web accessibility
principles such as those outlined in WCAG 2.0 (W3C
2008).
Stakeholder Involvement
Target group organizations (for AccessibleMap, the
Austrian Association in Support of the Blind and Visually
Impaired; for senTour, the Austrian National Council of
Disabled Persons) were involved throughout the devel-
opment process for both pilot web maps. ey support-
ed tasks related to gaining a deeper understanding of the
intended user groups, such as advising on suitable ques-
tionnaire design, getting in contact with the target groups,
and specifying user requirements.
OVERVIEW OF SELECTED RESULTS
RELEVANT AND USEFUL LITERATURE
E     only a few spe-
cific recommendations for creating, in particular, web
maps that meet the needs of the disabled (and in particular
the visually impaired), there is abundant literature that can
still be useful when developing such web maps.
Numerous standards and guidelines exist to enhance the
accessibility of digital and web-based products. ey provide
information on interface design, human computer interac-
tion, and the use of input/output devices that is helpful for
the development of accessible web maps. Examples include:
Focus of questions
Socio-demographic
and personal data
Age, gender, education level, place of
residence, type and degree of visual
impairment, etc.
Internet use
behavior
Extent of internet use, use of digital
devices, use of assistive technology,
etc.
Use of web maps
Extent of use, problems faced, web
maps used, assessment of web maps
used, etc.
User preferences &
needs related to the
web map design
Design and structure of the user
interface; design of (map) point, line,
and area features; and design of map
labels
Verbal description
of the map content
Preferred wording to describe certain
situations (e.g., crossings, course of a
road), content to be delivered, etc.
Table 3. Focus of the AccessibleMap questionnaire.

Cartographic Perspectives, FORTHCOMING Accessible Web Maps for Visually Impaired Users – Hennig et al. | 10
• WCAG 2.0 “Web Content Accessibility Guidelines”
• ISO/IEC TR 29138-1 “Information technology —
Accessibility considerations for people with disabili-
ties — Part 1: User needs summary
• ISO TS 16071 “Ergonomics of human-system inter-
action — Guidance on accessibility for human-com-
puter interfaces”
• ISO 9241-171:2008 “Guidance on software
accessibility”
• ISO/IEC 9241—20:2008 “Accessibility guidelines
for information/ communication technology (ICT)
equipment and services”
• IBM Developer Accessibility Guidelines
Useful information can also be found in usability guide-
lines and recommendations. In particular, the Nielsen
Norman Group (nngroup.com) has developed documents
focusing on the usability of digital and web solutions for
the visually impaired and the blind (see, for example,
Nielsen 1994; Nielsen 1996; Pernice and Nielson 2001).
Literature specific to special needs cartography, such as
Höckner et al. (2012) and Ienaga et al. (2006), delivers
recommendations on how to design maps that are suitable
for the intended user audience,
as well as discussing the map
content they require (e.g., infor-
mation in support of orientation
and way-finding). ere is also a
body of research related to maps
for the color vision impaired
(see, for example, Culp 2012;
Harrower and Brewer 2003;
Jenny and Kelso 2007; Olson
and Brewer 1997).
Verbal descriptions of map con-
tent are necessary to support the
blind in constructing cognitive/
mental maps. For this, literature
on behavioral geography is par-
ticularly useful: how the blind
navigate and orient themselves
in indoor and outdoor envi-
ronments, on navigation sys-
tems, on spatial cognition and
mental mapping (Ferguson and
Hegarty 1994; Millonig and Schechtner 2005; Tversky
1993; Giudice et al. 2007; Sánchez and Torre 2010).
QUESTIONNAIRE RESULTS
After removing invalid responses (such as those from users
who were not visually impaired), 158 of 199 AccessibleMap
project user questionnaires remained. Of those, 63% of the
respondents were people with low vision, while 37% were
severely visually impaired or blind. Table 4 provides an
overview of the respondents’ socio-demographic data, and
Figure 2 presents selected questionnaire results. Further,
the respondents named and commented on several city
web maps they used, including specific ones for Berlin,
Hagen, Mainz, Bern, and Vienna, as well as Google Maps
and OpenStreetMap.
Of the 197 managers of large protected areas to which the
first senTour project questionnaire was sent, 68 responded.
Collectively, respondents named more than 30 websites
or web applications that in one or another way were di-
rected to the target user group of the disabled and elder-
ly. Examples included the websites of Lüneburger Heide
Nature Park (Germany), Gesäuse National Park (Austria),
Dümmer Nature Park (Germany), Harz National Park
Table 4. Summary of respondents’ socio-demographic data in the AccessibleMap project
questionnaire.
Low vision &
color vision impaired users (n=99) Blind users (n=59)
Number of
Respondents
low vision: 59%;
color vision impaired: 4% 37%
Age
< 30 years: 11%
< 40 years: 9%
< 50 years: 13%
< 60 years: 10%
< 70 years: 14%
≥ 70 years: 2%
No data: 41%
< 30 years: 4%
< 40 years: 12%
< 50 years: 10 %
< 60 years: 10%
< 70 years: 5%
≥ 70 years: 0%
No data: 59%
Gender Female: 31%; Male: 37%
No data: 32%
Female: 24%; Male: 47%
No data: 29%
Education level
High school degree: 11%
University degree: 23%
Vocational training: 19%
Oth e rs: 14%
No data: 33%
High school degree: 17%
University degree: 27%
Vocational training: 17%
Others: 10%
No data: 29 %

Cartographic Perspectives, FORTHCOMING Accessible Web Maps for Visually Impaired Users – Hennig et al. | 11
Figure 2. Selected results from the AccessibleMap project questionnaire.
Use of devices by the visually impaired (multiple responses)
Relevance of visual variables in the map by the visually impaired
(multiple responses)
Preference regarding the description of directions
(severely visually impaired and blind users)
Preference regarding the description of crossings
(severely visually impaired and blind users)
Use of assistive technology by the visually impaired (multiple responses)
Use of the internet by the visually impaired

Cartographic Perspectives, FORTHCOMING Accessible Web Maps for Visually Impaired Users – Hennig et al. | 12
(Germany), Südschwarzwald Nature Park (Germany), and
Eifel National Park (Germany). e second senTour proj-
ect questionnaire, which was directed to web map users,
received 129 valid responses. Table 5 gives a summary of
respondents’ characteristics and Figure 3 presents selected
results.
BEST-PRACTICE EXAMPLES
e questionnaires and our internet research provided us
information about web (map) applications that in one way
or other met the needs of the target groups. Table 6 lists
and describes those applications with components that can
serve as a pattern or template for the development of web
maps accessible to the visually impaired.
RECOMMENDATIONS FOR THE DEVELOPMENT OF WEB MAPS
SUITABLE FOR VISUALLY IMPAIRED MAP USERS
A   in our Introduction, visually impaired
users face different problems when using web maps. ese
problems vary depending on the type and degree of their
visual impairment. Accordingly, we offer different recom-
mendations for the color vision impaired, the moderately
visually impaired, and the severely visually impaired or
blind (Table 7). These recommendations relate to user
interface design, map design, interaction modes, and the
verbal description of map content, each relevant in creat-
ing web maps accessible to these user groups.
Questionnaire Respondents (n=129)
Age
< 55 years: 24%
55–60 years: 16%
61–65 years: 24%
> 65 years: 34%
No data: 2%
Gender Female: 54%; Male: 44%; No data: 2%
Education level
High school degree: 19%
University degree: 29%
Vocational training: 36%
Others: 12 %
No data: 5%
Suffering from
visual impairment
Moderately visually impaired: 57%
Severely visual impaired or blind: 9%
Others: 34%
No data: 0%
Table 5. Summary of respondents’ characteristics for the senTour
project target group questionnaire.
Preferences about the amount of information to be delivered Use of the internet to get information to plan and prepare recreation trips
Figure 3. Selected results from the senTour target group project questionnaire.

Cartographic Perspectives, FORTHCOMING Accessible Web Maps for Visually Impaired Users – Hennig et al. | 13
Table 7. Requirements for users with different types and degrees of visual impairment.
Table 6. Selection of web applications addressing the needs of the visually impaired in one way or another.
Best-practice components
Google Maps
www.google.de/maps
Use of the keyboard to navigate the map
Optimal map design aspects:
• representation of different categories of roads with different colors (main/important roads:
yellow; smaller roads: white)
• representation of different categories of buildings with different colors
• presentation of different point of interest (POI) categories using different icons and colors
• labels do not overlap any POI symbols
Vienna city map (Austria)
www.wien.gv.at/stadtplan/en
User can select between different basemaps, including ones with high/optimized contrast (e.g., a
black & white basemap)
Use of arrow keys to pan around the map
Layer-switching control is located outside the map component
Presentation of different POIs with different icons and colors
High contrast between buildings (red) and roads (white)
Provision of emergency numbers
Bern city map (Switzerland)
map.bern.ch/stadtplan
User can select between different basemaps, such as a black & white one
Buttons with high contrast between text and background
German Railway
reiseauskunft.bahn.de
(after selection of start and end station,
press button map view)
Placement of zoom buttons outside the map component
Design of zoom buttons: large buttons with labels
Pan the map by arrow buttons located around the map component
Immoscout
www.immobilienscout24.de
(select object, scroll down to map)
Placement of layer selector outside the map component
Design of layer selector: large buttons with well-known symbols
Harz National Park (Germany)
www.nationalpark-harz.de
Website developed according to WCAG 2.0 principles: e.g., use of text-to-speech technology,
allowing users to choose higher contrast text and background colors, zoomable web page
Eifel National Park (Germany)
www.nationalpark-eifel.de
Website developed according to WCAG 2.0 principles: e.g., users can change font size, choose
higher contrast between the text and background colors, switch to a text-based version (with verbal
description of the content), or access verbal description of images
Lüneburger Heide Nature Park (Germany)
www.naturpark-lueneburger-heide.de/
aktiv-in-der-heide/naturpark-barrierefrei/
barrierefreies-natur-erleben/amelinghausen
Features a verbal description of the trail shown in a static map, including a general description of the
trail, and how to visit it
Verbally describes specic accessibility aspects of the trail, such as its length, conditions, material,
and the availability of barrier-free infrastructure
Color vision impaired Moderately visually impaired Severely visually impaired, blind
User interface
design
General user interface
design guidelines
Depending on the type and degree of visual
impairment:
general user interface design guidelines
application of web accessibility principles
General user interface design
guidelines
Application of web accessibility
principles
Map Optimized visual design Optimized visual design
Interaction mode Visual Visual and auditory Auditory
Verbal description of
map content Nice to have Depending on the degree of visual impairment Mandatory

Cartographic Perspectives, FORTHCOMING Accessible Web Maps for Visually Impaired Users – Hennig et al. | 14
USER INTERFACE DESIGN AND STRUCTURE
As outlined by Tsou and Curran (2008), the user inter-
face is the prime factor that decides upon the fate of any
software application—in the worst case, even determining
whether or not an application is used at all. For accessible
applications and websites, an appropriately designed user
interface is even more important (Hung 2001; Jacobson
1998; TTC 2013).
Web maps are a special kind of web application. Apart
from elements common to other web applications, such
as orientation and navigation tools, messaging systems,
help components, and setting tools, web maps have a map
component that is embedded in their graphical user inter-
face (GUI). is map component itself also comes with
several of its own elements: navigation tools for panning
and zooming the map, feature pop-up windows, layer and
basemap selectors, etc. Like the GUI, the map component
(including its related elements) must be accessible and de-
veloped in line with user needs.
Arrangement of Components
To ensure an application is easy to use, its user interface
should be kept simple and consistent, and follow a clear,
predictable layout (Nielson 1994; W3C 2008). Achieving
this involves the careful selection and arrangement of in-
dividual interface components. Since these components
are usually linked to specific functions, user interface de-
sign depends on the range of functions implemented. In
order to benefit the target group, user interface complexity
can be decreased by considering the following guidelines
(which mostly refer to the development of desktop GUIs):
• implement only as many control elements as necessary
and as few as possible—check for unnecessary ele-
ments and remove them (Guenga et al. 2006);
• control elements with similar focus should be grouped
with each other—but at the same time, avoid group-
ing too many elements at once (Pernice and Nielsen
2001; W3C 2008);
• locate control elements of the same type in the same
place across similar programs (as is done, for example,
by Microsoft Office applications) (W3C 2008);
• provide a flat and horizontally organized interface
structure, with no dropdown or nested elements
(Pernice and Nielsen 2001);
• avoid or reduce scrolling, so that all (critical) elements
are visible and accessible without scrolling the screen
(Pernice and Nielsen 2001); and
• avoid overlapping of elements (WAWG 2014).
The last point is particularly relevant for web maps. In
these applications, basemap selectors and navigation tools
are often placed within the map component, which makes
it difficult for visually impaired users to read the map as
well as to recognize and use control elements. Interaction
tools (e.g., for zooming and panning, or selectors for base-
maps and overlays) should be located outside the map com-
ponent. ey should not cover parts of the map. Taking
into account the AoSS results (Table 6), Figure 4 illus-
trates an arrangement of the map component and related
elements within the GUI that is optimized to support the
visually impaired.
Visual Design of Components
An appropriate visual user interface design makes it easi-
er for users to perceive, understand, and operate an appli-
cation (ITU/G3ict 2014b). To assist users, interfaces and
their components must be implemented in a suitable size.
Likewise, colors should be chosen to provide high contrast
between elements such as text, buttons, and checkbox-
es. Complex background, such as pattern fills, should be
Figure 4. Sketch of a web map layout that is designed for easier
access by the visually impaired.

Cartographic Perspectives, FORTHCOMING Accessible Web Maps for Visually Impaired Users – Hennig et al. | 15
avoided. Symbols should be well known to users and intu-
itive to understand (ITU/G3ict 2014b; W3C 2008; Figure
4).
Language Used
To make information accessible (i.e., understandable), the
careful use of language plays an important role (W3C
2008). is is relevant not only to visually impaired users,
but to all non-expert users of spatial data products. Hennig
and Vogler (2016) state that laypersons often refuse to click
buttons labeled with (technical) terms unknown to them;
they instead close the application. Hence, all terms used
throughout an application must be familiar to the users.
Simple and user-focused language as well as consistent se-
mantics should be used (W3C 2008).
MAP
A map that is as easy as possible to read increases success
in communicating the content to the users (Kraak and
Ormeling 2010). is is especially relevant for people with
reduced vision or those affected by color vision impair-
ments. A thoughtful choice of visual variables (size, shape,
position, pattern, arrangement, and color) to create point,
line, and area symbols can make the difference between
a map being easy or difficult to read (Christophe and
Hoarau 2012; Muehlenhaus 2014). The AccessibleMap
project questionnaire results confirm the importance of
visual variables in creating a visual design suitable for visu-
ally impaired users (Figure 2).
Hung (2001), as well as Jeffrey and Fendley (2011), sug-
gest that size and color (e.g., no garish colors, but saturated
and bright colors), and increased contrast settings between
features such as buildings, streets, parks, places, points of
interest, annotations etc. are important aspects to consid-
er in the appropriate presentation of map features to the
target group. Since patterned areas and lines are easier to
recognize and to distinguish than areas or lines with col-
oring only, Jenny and Kelso (2007) recommend combining
coloring with simple patterning to enhance map readabil-
ity. ey also suggest that feature labeling (e.g., buildings,
streets, parks, and rivers) is helpful for the user group to
understand the map content. A selection of recommenda-
tions on the usage of visual variables for map features and
text elements (labels, annotations, pop-ups, etc.) is listed
in Table 8. ese recommendations are not only important
for building basemaps, but also for displaying overlays
(such as points of interest) on maps.
One way to meet the (different) map needs of moderately
visually impaired and colorblind users is to provide a set of
basemaps the user can choose from. us, for instance, the
Vienna and Bern city web maps permit the user to switch
between a standard basemap and a black and white ver-
sion. e high contrast between black and white makes
these basemaps particularly useful for visually impaired
users. To optimize color contrasts, color contrast ratio and
related recommendations are useful (for instance, those
presented in detail in W3C [2008]). Finally, tools such as
ColorBrewer (colorbrewer2.org), Color Oracle (colorora-
cle.org), or Color Contrast Checker (webaim.org/resourc-
es/contrastchecker) can be used to create and test color vi-
sion impaired-friendly designs.
Due to the different types and degrees of visual impair-
ment, the literature suggests permitting user adjustment
of contrast, symbol size, line width, color combinations,
and color brightness (Andrews 2007; Jeffrey and Fendley
2011). is is confirmed by the AccessibleMap question-
naire results (Figure 2): 77 % of the respondents would
prefer to be able to adjust one or more visual variables in
the map themselves.
INTERACTION MODES
Currently, user interfaces are usually implemented as
GUIs. e users interact with the system through menu
bars, icons, and windows; these interactions are handled
by input devices such as mice, keyboards, or touchscreens.
Information is returned as a graphical display on the de-
vice’s screen. Since GUIs rely heavily on the visual sense,
people who are severely visually impaired or blind are at a
disadvantage. However, supporting keyboard accessibility,
as well as using assistive technology, can be pivotal to a
solution.
Keyboard Accessibility
Keyboard accessibility is important for improving the op-
erability of web maps for visually impaired users (Langen
and Ballantyne 2014; Victorian Government 2011; W3C
2008). Many severely visually impaired and blind users
typically use a keyboard to navigate applications. Even
for users who are partially sighted, the use of a keyboard
provides easier access to web content (WebAIM 2016).

Cartographic Perspectives, FORTHCOMING Accessible Web Maps for Visually Impaired Users – Hennig et al. | 16
In addition to addressing commonly relevant aspects of
keyboard accessibility, such as the provision of focus in-
dicators or the definition of a navigation order (WebAIM
2016), map control elements must be designed and imple-
mented in a particular way. Map navigation tools should
provide pre-defined, discrete zoom and pan steps that are
tied to keyboard shortcuts, permitting the user to navi-
gate around the map without using a mouse. In Google
Maps, for example, to move the map north or south in
small steps, the arrow-up or -down keys can be used; to
move the map north or south in large steps, the page-up or
-down keys can be used (Table 6).
Assistive Technology
Assistive technology refers to any object or system direct-
ed toward aiding people with disabilities in interacting
with their environment, in communicating with others,
and in accomplishing a variety of tasks. With regard to
digital products, assistive technology refers to technology
that supports users in accessing and using software appli-
cations and websites (W3C 2008).
Among existing assistive technology tools, voice out-
put, screen readers, Braille displays, and magnification
Recommendations
Points
• Simple symbols and glyphs (Gill 2009; Harley 2014)
• Widely/well-known icons (Jeffrey and Fendley 2011)
• Appropriate color design: use of bright colors (Liu 2010); optimized color contrast between symbol and background,
symbol and surrounding items (Fowler 2011; Jenny and Kelso 2007) according to the color contrast ratio as discussed in
WCAG 2.0 (W3C 2008)
• Different colors and icons for different features (Jenny and Kelso 2007)
• Adequate size of symbols and glyphs—this depends on a number of parameters such as the user, complexity of the
symbol, display qualities, and viewing conditions; thus, the minimum acceptable symbol size has be tested by the
intended user group (Gill 2009)
Lines
• Lines should not be too thin, however appropriate thickness depends on color use and color contrast to the background
(see, for example, Gill 2009; W3C 2017)
• Appropriate color design: use of bright colors (Liu 2010); optimized color contrast between lines and other elements
(Jenny and Kelso 2007) according to the color contrast ratio as discussed in WCAG 2.0 (W3C 2008)
• Different colors to represent different types of lines (Galvin 2014; Jenny and Kelso 2007)
• In addition to color, use different line thickness and patterns to represent different types of lines (AccessiQ 2015; Galvin
2014; Jenny and Kelso 2007)
Areas
• Use dark outlines (see, e.g. Liu 2010)
• Appropriate color design: use of bright colors (Liu 2010); optimized color contrast between lines and other elements
(Jenny and Kelso 2007) according to the color contrast ratio as discussed in WCAG 2.0 (W3C 2008)
• To distinguish different types of areas, use patterns in combination with colors (Jenny and Kelso 2007; W3C 2016)
Text
• Optimize color contrast between text and background, or between text and surrounding text; black letters on a white
background are considered best practice (Fowler 2011; Jeffrey and Fendley 2011; W3C 2016)
• Use of simple, well-established, and popular sans serif typefaces (Jeffrey and Fendley 2011)
• No underlining or italicizing of characters (Jeffrey and Fendley 2011; W3C 2016)
• Only the rst character of a word should be capitalized (if any are at all), others are written in lower case letters (W3C
2016)
• Suitably large font size: guidance on type size varies from recommending 12 to 18 point type (Jeffrey and Fendley 2011;
W3C 2008)
• Left-aligned (Jeffrey and Fendley 2011)
• Not overlapping with other features or labels (WAWG 2014)
Table 8. Recommendations on how to employ visual variables to design a map suitable for visually impaired users.

Cartographic Perspectives, FORTHCOMING Accessible Web Maps for Visually Impaired Users – Hennig et al. | 17
software are the most popular (Bártek and Kopeček 2006;
Leporini and Paternò 2008). e importance of assistive
technology for our target group is confirmed by the results
of the AccessibleMap questionnaire (Figure 2): among
moderately visually impaired users magnifier software is
used most frequently (38%), while the severely visually im-
paired and the blind primarily use Braille displays (89%),
voice-over (89%), and screen reader software (79%).
Screen magnification is relatively easy to implement using
existing software tools (such as Virtual Magnifying Glass)
or custom-programmed solutions (using, for example,
JavaScript libraries).
In contrast to this, Braille displays, screen readers, and
voice-over software, require specific applications to be
installed by the user. If needed, external devices such as
Braille displays must also be available. To support these
options, text alternatives for every non-text element (in-
cluding the map itself ) must be available. Depending on
the tool, text alternatives are read aloud (screen reader,
voice-over) or are delivered as tactile output (Braille dis-
play). Very short verbal descriptions (~125 characters) of
images (including embedded static web maps) are usual-
ly provided using the ALT-attribute/ALT-tag in HTML
(Nielsen 1996; Penn State Accessibility 2015b). To deliver
more detailed descriptions of non-text elements than the
ALT-tag can offer, or to provide any kind of verbal in-
formation about dynamic/interactive web maps, text can
be presented in separate components (such as additional
browser tabs) related to the map (Table 6: Lüneburger
Heide Nature Park; Eifel National Park).
VERBAL DESCRIPTION OF THE MAP
CONTENT
As outlined in the literature, maps (as well as other non-
text elements such as images or diagrams) should be pro-
vided with both a brief sentence-length description as well
as a more detailed one (Penn State Accessibility 2015a;
Victorian Government 2011; W3C 2008). e availability
of a brief explanation was considered particularly import-
ant by the majority of senTour project user questionnaire
respondents (Figure 4).
A short comment on the map’s content can usually be cre-
ated without any difficulty, since it is usually a simple and
static text that delivers a general overview of the map and
its content via the use of the ALT-tag. In contrast to this,
writing a more comprehensive verbal description of (inter-
active/dynamic) map content is a challenge (see, for exam-
ple, Ferguson and Hegarty 1994; Jacobson 2002): apart
from information about individual features (“bus stop,”
“street,” “crossing,” etc.), a holistic overview of an area of
interest has to be given. This must include information
about the relationships and distances between different el-
ements (for example, “this shop is located on Main Street;
it is twenty meters away from the intersection of Main
Street and 3rd Avenue”).
Amount of Information
Since people usually can only remember a limited number
of things at a time (on average seven, according to Nielsen
[2009]), the amount of information an application delivers
must be in line with this. Users should not be overloaded
with too much detail. Detailed descriptions should focus
on certain locations (e.g., selected by the user or user’s cur-
rent position; Giudice et al. 2007).
Here, to understand an entire map, a user can start at a
selected location and then move virtually along streets or
trails, receiving information on each section along the way
(Figure 5). As the user moves around the map, step by
step, a comprehensive description of its content is given.
This enables the user to explore the map gradually and
build up a cognitive map of an area without using the vi-
sual sense.
Figure 5. Example approach to deliver a verbal description on the
map content (adapted from Wasserburger et al. 2011).

Cartographic Perspectives, FORTHCOMING Accessible Web Maps for Visually Impaired Users – Hennig et al. | 18
Order of Information
The order in which information is presented should be
in accordance with its relevance to the user, prioritizing
key elements for the construction of a cognitive map such
as reference points or cues (landmarks), first and, sec-
ond, paths, streets, or trails (Ferguson and Hegarty 1994;
Millonig and Schechtner 2005; Tversky 1993). is ap-
proach is particularly important for people who are blind,
since they usually walk linearly along a chain of orienta-
tion points. However, the landmarks, orientation points,
and points of interest used by the blind are often differ-
ent from those of the sighted. e blind consider elements
such as acoustic traffic lights, tactile guiding systems,
or type of pavement to be relevant (Ienaga et al. 2006;
Jacobson 1998).
Information on Distance and Direction
Distance information should be provided using both met-
ric and walking time measurements (Kalia et al. 2010).
Information on direction should be provided based on
using body-orientation indications (left, right, forward,
backward, etc.), the cardinal points system (north, south,
east, west), or the hour system. The hour system uses a
metaphor to indicate directions: the user is imagined to
be in the center of an analog clock, with 12:00 to their
front, 3:00 to their right, 6:00 directly behind them, 9:00
to their left, and so on (Sánchez and Torre 2010). The
AccessibleMap project questionnaire’s results underline
the hour system’s relevance for describing directions: 49%
of the respondents prefer it (Figure 2). e AccessibleMap
questionnaire respondents also preferred pedestrian cross-
ing layouts to be described using letters (e.g., T-, V- or
X-crossing; Figure 2).
Today, verbal descriptions of map content can often be
generated automatically using spatial databases and geo-
graphic information systems. is allows the description
to be adapted whenever the user selects a new location on
the map, or whenever the map content changes due to user
interactions (zooming, panning, switching layers, etc.).
ADDITIONAL CONSIDERATIONS IN INCREASING ACCESSIBILITY
T   in the AccessibleMap and sen-
Tour projects allowed us to not only develop recommen-
dations about what to consider when creating web maps
that are accessible to the visually impaired, but also made
it obvious that additional aspects should be considered to
enable these users to benefit fully from web maps.
ACCESSIBILITY AND RELATED CONCEPTS
As we discussed above, web accessibility focuses on the
removal of technical barriers that might hamper people
with disabilities from accessing information. However, it
does not explicitly address other, equally important con-
siderations. But, accessibility alone is not enough: usabili-
ty, utility, and compatibility must additionally be consid-
ered (Table 9). Together, these four concepts, which are
closely intertwined with each other, provide a framework
of characteristics for products that aim to be well suited
for disabled users (ITU/G3ict 2014a; ITU/G3ict 2014b;
Leporini and Paternò 2008). In consequence, the concept
of accessibility must be considered broadly.
e terms usability and accessibility are closely related,
but each has a different focus, though their objectives,
approaches, and guidelines overlap significantly. Krug
(2006) suggests that a website (or any product) is not us-
able unless it is accessible, and Brajnik (2000) stresses that
accessibility is a subset of usability.
Description
Accessibility Extent to which the product is usable by
people with the widest range of capabilities
Usability
Extent to which the product can be used by
specied users to achieve specied goals with
effectiveness, efciency, and satisfaction, in a
specied context of use
Utility
Extent to which the product provides
functionality that meets real user needs, such
as those associated with independent living
and participation in society
Compatibility
Extent to which the product works together
with other devices, and conforms with current
technical standards, guidelines, and laws
Table 9. Criteria closely linked to accessibility (based on ITU/
G3ict 2014 a).

Cartographic Perspectives, FORTHCOMING Accessible Web Maps for Visually Impaired Users – Hennig et al. | 19
The same is true for utility and compatibility: websites
and web applications must not only be accessible, but they
must also provide content, functionality, and access to de-
vices relevant to its users. us, for instance, our intended
user group requires functionality that permits the use of
assistive technology. Further, apart from the information
commonly found in web maps (e.g., streets, places, build-
ings, parks, and rivers; Horstmann et al. 2006), visually
impaired users require information on specific infrastruc-
ture (e.g., guidance systems, accessible parking, toilets,
and public transportation) and feature characteristics
(i.e., tactile, audible, and smellable). Such elements play a
particularly important role in helping the blind to orient
themselves in physical space and to engage in wayfinding
(Ienaga et al. 2006; Karimi et al. 2014).
DIGITAL AND SPATIAL LITERACY
e questionnaire results obtained in the AccessibleMap
and senTour projects highlight the widespread usage of in-
formation and communication technology (ICT) among
the target group: the majority of the AccessibleMap proj-
ect questionnaire respondents
indicated they use desktop PCs,
laptops, smartphones, and tab-
lets, and that they use the inter-
net several times a day (Figure
2). The senTour project target
group questionnaire showed
that 73% of the respondents
use the internet to get informa-
tion about recreation or tour-
ism (Figure 3). ese results are
consistent with the findings of
Harris (2010), who stated that
disabled people engage enthusi-
astically with technology.
Despite their high usage of ICT,
the target group considered
the use of the internet and of
web maps to be a complex task
(Höckner et al. 2012). In this
context, Guenga et al. (2006,
287) suggest that “better skills
using technologies and ICT,
make a big difference.” Here,
“skills” refers to digital skills
and competencies that enable
users—who today are acting
as prosumers (both consumers
and producers) of spatial data
(Rinner and Fast 2015)—to
handle web maps in a competent
and capable manner (Table 10).
Measures to foster these skills,
which are still often missing
in society, are desired, includ-
ing appropriate user support,
help and tutorials, as well as
Selected skills and competencies Users as
Digital skills
Register/login including self-representation, prole creation, identity
management, etc. Prosumer
Use, create, remix, publish, share, embed content and objects (using
different web 2.0 tools) Producer
Network (search, combine, disseminate information) and negotiate
(travel across diverse communities, discerning and respecting
multiple perspectives, etc.)
Prosumer
Work in a cooperative way Producer
Judge/evaluate the reliability and credibility of information sources Prosumer
Internet safety issues: copyright, data privacy, etc. Prosumer
Understand the logistics of cloud-based interleaving of services and
media Producer
Abilities to
handle spatial
data products
Know and understand basemaps and layers Prosumer
Use basic functions of digital maps (nd, open, zoom, pan, etc.) Prosumer
Create maps and features (add markers, lines, areas, labels) Producer
Add additional information (using information windows/feature
pop-ups) Producer
Handle data les (import, export, convert, transfer) Producer
Output maps (print, save, export, embed, share) Prosumer
Re-use data (nd data, assess data, process data, integrate data) Prosumer
Capabilities to
handle spatial
data products
Know relevant vocabulary and technical terms (e.g. layer, basemap,
POIs) Prosumer
Cartographic design guidelines: decide upon adequate symbols,
map image, background map, combine multimedia and geo-media Prosumer
Multimedia use (add, post, comment) Prosumer
Critical reection on the power of maps Prosumer
Use maps as a powerful mediator and communication means of
interests Prosumer
Table 10. Selected skills allowing users to use spatial data and spatial data products in a
competent and capable manner (adapted from Hennig et al. 2013).

Cartographic Perspectives, FORTHCOMING Accessible Web Maps for Visually Impaired Users – Hennig et al. | 20
education and training offers. It is widely accepted that
such measures to strengthen spatial literacy are equally
important as providing accessible applications (Hennig et
al. 2013).
PARTICIPATORY DESIGN
e methods used in the AccessibleMap and senTOUR
projects—literature and internet review, user survey,
AoSS, and stakeholder involvement (Figure 1)—are
well-recognized in software engineering and requirements
engineering. But, applying them might not be enough to
gain a profound understanding of users. Reasons include
communication problems between users and develop-
ers (misunderstandings, use of different vocabulary, etc.),
users’ lack of awareness of their own needs, and users’ lack
of ability to reliably describe their requirements (Firesmith
2007; Hennig and Vogler 2016). Direct and active coop-
eration with future users in the application development
process can be seen as a remedy to these shortcomings,
using the approach of participatory design.
Participatory design is defined as a process that aims at
involving representatives of future users in the design
and development process of a system or product. is can
occur in different ways and with varying intensity (Baek et
al. 2007). A distinction is made between weak and strong
participatory design: in weak participatory design, even
though user input is solicited throughout the entire devel-
opment process, decision making is largely undertaken by
the developers. In strong participatory design, the users
take part in decision making. Detailed information on
participatory design can be found in the literature (see, for
example, Enerson 2013; Mazzone and Read 2005; Steen
et al. 2007).
Several advantages of participatory design are laid out in
Table 11. Because users are experts in their own require-
ments, participatory design exposes user needs and skills
(as tacit knowledge: aspects usually not known to devel-
opers) and brings them into the development process. is
helps to generate applications that better adhere to users’
aims (Muller and Druin 2012; Steen et al. 2007), which
is particularly relevant for the development of web maps
that address laypersons and/or special needs users such as
disabled people, the elderly, and non-adults. Tsou (2003)
stresses that the developers of web maps are challenged
with meeting the needs of non-experts, who are a lot more
diverse and unfamiliar to the developers than are tradi-
tional GIS users. Hennig and Vogler (2016) further ex-
plain that special needs users, including visually impaired
users, are even more unknown to web map developers.
us, the participatory design approach can play a critical
role in the development of accessible web maps.
CONCLUSION AND OUTLOOK
T     is as important for the visually
impaired as it is for sighted people, and sometimes it is
even more important. Having access to spatial information
regarding unknown areas allows them to plan and prepare
trips in advance; this can lead to a more independent life.
Since accessible web maps focus on enabling everyone to
Advantages
General • Developers get to know users; they learn profoundly about user abilities, use purposes, and life circumstances
• Prevent and reduce problems of communication and misunderstanding between developers and users
• Users offer a source of new ideas
Development
process
• Valuable user input
• Address users’ lack of awareness of their own requirements and their inability to outline these reliably
• Support developers to identify, describe, and fully recognize user requirements
• Avoid undesirable developments
Afterwards • Guarantee that the application aligns with user needs/demands and that it delivers a good user experience
(focusing, for example, on accessibility, usability, utility, compatibility, and desirability)
• Increase user knowledge and acceptance of the application
• Ensure that the implemented product really meets the needs of the user group
Table 11. Selected advantages of participatory design (Hennig and Vogler 2016).

Cartographic Perspectives, FORTHCOMING Accessible Web Maps for Visually Impaired Users – Hennig et al. | 21
benefit from ICT, including the internet, these applica-
tions can be seen as a contribution towards e-inclusion,
and strengthening the information society.
Even though visually impaired users may require special
solutions depending on the type and degree of their visual
impairment, the following recommendations are of gener-
al interest when developing web maps accessible to them:
provide an easy-to-use and well-designed user interface
with a well thought out range of implemented functions;
create an easy-to-read map picture; support different in-
teraction modes (including use of assistive technology);
and give a verbal description of the map content.
Due to these issues web maps accessible to visually im-
paired users are different from conventional web maps.
ey feature added flexibility, alternative modes, and more
choices for their users. But making web maps accessible
to disabled users does not mean that they become any less
useful for others. To the contrary, increased accessibility
often results in improved design for everyone, as it makes
applications easier to use and more attractive.
In support of building applications tailored to the visually
impaired, several standards and guidelines exist, but there
are very few recommendations that provide guidance on
creating accessible web maps, specifically. is gap needs
to be filled. We refer not only to the provision of these
recommendations, but also to the elaboration of design
patterns, describing and presenting best-practice solutions,
which should be evaluated by experts and target groups.
Having such information at hand would be helpful to de-
velopers who are designing and implementing accessible
web maps.
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