Symbols for Indoor Maps

Indoor maps are most often in the form of architectural plans, which contain much information about specific structural features. However, these maps are usually not publicly available because they were created for the design and construction of a building and are not suitable for the exploration of a new building. For example, the shape of a building, arrangement of rooms and corridors, doorways, and points of interest in a building are relevant when exploring a new building. For people with disabilities, additional information about a building which are not included in standard maps is important. These accessibility features include e.g. the presence of voice output, handrails, ramps, information about door widths, or tactile information.  These indoor maps need to be designed in such a way that all information can be easily recognized and read. Thus, the map design, including the symbols, must be created to meet the specific requirements of the target groups. The AccessibleMaps project addresses the creation of three different sets of symbols: tactile, acoustic and visual symbols for indoor maps.

Contents:


Tactile symbols

Tactile maps are a way to make spatial information accessible to people with blindness. They can be explored by touching them with the fingers or palm of the hand. There are different printing techniques to create these maps: printing on swell paper, embossing on thicker paper, printing with braille printers, thermoforming or even 3D printing. They differ not only in the material used, but also in their resolution. This means that certain elements, such as a line, are represented as a solid line on swell paper and by closely spaced dots in embossed printing. The difference in resolution affects which symbols can be used and how.

In recent years, there have been a number of studies that investigated the recognizability of tactile symbols. Much of this research has been done for print using swell paper. Since both swell paper and embossed printing are used in the AccessibleMaps project, we investigated  which of the symbols that are easily recognizable on swell paper are also suitable for embossed printing. In a user-centered approach, meanings were assigned to the symbols. The approach as well as the results are described in more detail in the ICCHP 2022 paper “The Accessible Tactile Indoor Maps (ATIM) Symbol Set: A Common Symbol Set for Different Printing Methods“.


Audio symbols

When visiting unknown buildings, people with blindness rely mainly on their hearing for finding their way and navigating safely. Information about accessibility features in the building plays an important role in the orientation of this users group. But in order for it to be useful, this information must be carefully presented, so as not to overload the users or even threaten their safety. Similarly to visual symbols, audio symbols have the potential to convey information so that it stands out, while reducing the learning curve for new users of a system and saving on information transmision time. Thus, the sounds used must be very short and intuitive.

In the AccessibleMaps project, we are creating a small database of auditory icons for 38 categories of so-called „objects“ that are relevant for the accessibility of spaces, such as: stairs, toilets, door, room, elevator, service point, etc. One category can contain several „objects“ – for instance, the category „eating place“ consists of the objects: „cafeteria“, „kitchen“ and „vending machine“. These „objects“ help people with blindness to orient themselves, to move safely or to find points of interest – in short, they improve greatly the navigation experience.

In creating the sounds database, we applied a recursive, user-centered design. In a first step, we asked the end users, in an online survey, about the sounds that they associate to everyday „objects“ – or, in other words, we identified the conceptual mappings of the auditory icons. In a second step, the sounds were created, in a recursive co-design and testing together with one blind hobby musician. Finally, the sounds will be evaluated by target users, in an online questionnaire, for intuitiveness, attractiveness and conflicting mappings. The resulting sounds database will be published under an open license.


Visual symbols

Conventional visual maps mostly use symbols to locate information about points of interest (POIs) on the map. However, there is no uniform standard that is used in all common building maps and applications. Therefore, according to the design for all concept, a set of visual symbols is designed that can be used especially by people with visual impairments and/or mobility impairments. Here, emphasis is placed on good recognizability of the individual symbols as well as when used on a map. In addition, the meaning of the symbols should be intuitive and a longer learning phase should be avoided.

To ensure a uniform design of the symbols, design guidelines will be developed and published later in the project. Basically, 3D effects within the symbols will be avoided in order to improve the recognizability. The color scheme of the symbols is chosen in such a way that they are easily invertible. For this reason, a black and white design is used.

Visual symbols are thereby designed for 13 accessibility features important to the target group. These include:

  • elevator
  • entrance
  • emergency exit
  • food facility
  • shopping facility
  • restroom/toilets
  • wheelchair accessible toilet
  • stairs/staircase
  • step
  • ramp
  • infopoint
  • danger
  • other as a collective symbol for further information on POIs that do not have their own symbol

Further information on the above-mentioned features is provided to the user by means of interaction and is not part of the symbol set.

At the moment, designed visual symbols are evaluated in terms of their recognizability, associated semantics, size and aesthetics. This is done both stand-alone and in the context of a visual digital map.