SVG Maps for People with Visual Impairment

SVG OPEN Conference July 2003

Keywords: svg mapping, blind, vision impaired, visually impaired, accessibility, haptic, braille, voice, multi-modal interface

Benjamin Campin, Mr
SVG / GIS Developer
DBx Geomatics
Hull
Quebec
Canada
bc@dbxgeomatics.com
http://www.dbxgeomatics.com

Biography

As a software developer and engineer for DBx Geomatics, Benjamin works on interactive web mapping applications using JavaScript and XML. He is an active member of DBx GEOMATIC'S software development team and is dedicated to the research and development of online mapping using SVG technology. He is presently collaborating with Natural Resources Canada with regards to the production of interactive SVG maps for persons with visual impairment.

William McCurdy, Mr
President
One World Software Services
Ottawa
Ontario
Canada
wamccurdy@rogers.com

Biography

Bill McCurdy is an expert systems analyst with over 23 years experience leading software development and system implementation projects. He has extensive experience with requirements analysis, test planning, documentation, configuration management, system implementation, and database management. His more recent focus has been web accessibility issues and mapping for the visually impaired.

Louis Brunet, Mr
Principal
Motus Creative
Ottawa
Ontario
Canada
motuscreative@sympatico.ca
http://www.tamas.com/motus

Biography

Louis Brunet has over 25 years experience in multimedia, graphic design, and project management. While at Nortel Networks he introduced the use of video streaming as a cost effective way to provide employee training. During the nineties, at Nortel, he founded and led a multimedia team capable of producing product marketing multimedia collateral integrating web, Flash, 3D animation and video. More recently his focus has been web related projects and accessibility.

Eva Siekierska, Dr
Research Project Manager
Natural Resources Canada
Ottawa
Ontario
Canada
siekiers@NRCan.gc.ca
http://tactile.nrcan.gc.ca

Biography

Dr. Eva Siekierska works as Research Project Manager - Mapping for Visually Impaired, at Mapping Services Branch of Earth Sciences Sector, Natural Resources Canada. She also holds an Adjunct Research Professor position at Carleton University. Her main research interests are: tactile and audio-tactile mapping, web accessibility and usability, multi-modal user interfaces and web-based visualization in application to sustainable development decision making.


Abstract


This paper will present the use of Scalable Vector Graphics (SVG) accessibility and interactivity to help people with visual impairment read audio-tactile maps. Scalable Vector Graphics contains designed-in accessibility features such as graphic scalability (useful for people who have low vision), sound effects integration, and description tags. Multi-modal communication, such as sound mode (sound effects, voice annotation), touch mode (haptic mouse, touch tablet), and visual mode comprise the interactive features and enhance the accessibility of these maps. The method used to produce such maps will be described in this paper. The current and potential uses for these maps addressed within this project are education, mobility, transportation, tourism and community development (Web-4-All project carried out in cooperation with Industry Canada).


Table of Contents


1. Introduction
2. Background Information
     2.1 Mapping for Visually Impaired Project
     2.2 SVG Mapping
3. Interactive Audio-Tactile Maps
     3.1 Tactile Maps
     3.2 Audio-Tactile Maps
         3.2.1 Set up the Map
         3.2.2 Read the Map
     3.3 Haptic Effects
4. SVG Maps Creation
     4.1 Methodology
     4.2 System Requirements
     4.3 Coding the Interactive Features
         4.3.1 Voice Annotation
         4.3.2 Haptic Effects
         4.3.3 Sound Effects
5. User's Feedback
6. Conclusions and Future Directions
Footnotes
Acknowledgements
Bibliography

1. Introduction

For persons with visual impairment getting and using something as simple as a map of the city they live in can be a big challenge. Improvements in technology and reduction in costs now make it possible to produce tactile maps economically. Web-related technologies are emerging that make map-based information accessible online for those who need it most. The flexibility of the SVG format and the interactive features of the maps created with it, significantly enhance the user experience. For the blind user, tactile, audio, and haptic effects [1] convey the information that a sighted person would primarily receive visually. During this project we created visually simple maps. But we have found that uncluttered maps can still be packed with information. The reduction in visual complexity is compensated for by an increase in information conveyed by audio or haptic means. The current and potential uses for these maps are education, mobility, transportation, tourism, and community development. Audio maps could be also useful to sighted people.

2. Background Information

2.1 Mapping for Visually Impaired Project

The Mapping for People with Visual Impairment project was initiated in 1998 as part of an international project in which Natural Resources Canada participated. That project, "Cybercartography for Latin America", was directed by the Pan American Institute of Geography and History (PAIGH) and Carleton University in Ottawa; financed by the World Bank, the United States Agency for International Development (USAID) and the Canadian International Development Agency (CIDA). Within this project, the "Tactile Atlas of Latin America" was produced. Due to the lack of tactile maps in Canada, the Canadian government decided to produce the Tactile Atlas of Canada, using new "raised ink" technology [SIEKIERSKA, 2001 ] . The atlas received very good reviews from blind children and teachers; the largest residential school for the blind pre-ordered copies of the atlas before it was available on the market. To continue this project, external funding was necessary. Natural Resources Canada applied for Government On-Line (GOL) funding for a Pathfinder innovation project. Subsequently it became a partner with Human Resources Development Canada (HRDC), Transport Canada and Industry Canada to develop a "Persons with Disabilities Cluster" web portal.

2.2 SVG Mapping

Mapping represents a perfect application of SVG, because maps are, by nature, vector layered representations of the earth. The SVG grammar allows the same layering concepts that are so crucial to Geographic Information Systems (GIS). Since maps are graphics that depict our environment, there is a great need for maps to be informative and interactive. SVG provides this interaction with very high quality output capability, directly on the web. Because of the complexity of geographic data (projection, coordinate systems, complex objects, etc.), the current [SVG Specification] does not contain all the particularities of a GIS particularities. However, the current specification is sufficient to help the mapping community produce open source interactive maps in SVG format.

3. Interactive Audio-Tactile Maps

3.1 Tactile Maps

Until recently, the use of tactile maps has been very limited, as most of the maps have been produced by hand, for example using string and glue, a very slow process. Recent developments facilitated the production of cost effective maps. Examples are:

3.2 Audio-Tactile Maps

The purpose of interactive audio-tactile maps was to provide a multi-modal environment thereby making all the rich geospatial information available and accessible to people with visual impairment. Placement of a tactile map on a touch tablet [2] allowed the user to interact with the SVG map. Sound effects were added using pre-recorded sounds. Voice annotation was implemented using text-to-speech software or screen reader software.

3.2.1 Set up the Map

The user found a map on the Mapping for Persons with Visual Impairments (MVI) web site and downloaded and printed the corresponding PDF file. The printout was run through a thermal enhancer [3] . This device raised the ink so that lines became recognizable to the touch. The printed map was then placed on a touch tablet.

illustration_1.png

Figure 1: The user finds a map

3.2.2 Read the Map

Once the map was placed on the tablet and carefully registered with the same image on the monitor, the user could trigger events. The finger of the user interacted with the SVG maps as a mouse device. When the user slid his finger over an element, a sound effect was heard. When the user wanted more information on a feature, a simple tap of the fingertip caused the name of that feature to be spoken by the user's screen reader. Using this method, we were able to label any element on the map.

illustration_2.png

Figure 2: The user reads the map

NOTE: This method for reading maps required some training as the users had to switch from exploring with all fingers like they were used to, to using a single finger as the computer expected - there is only one cursor!

The project team recommended that the user explored the map offline first, to become familiar with the basic geospatial information it contained. Then the user could move to the interactive map to access the additional information accessible through the haptic and sound effects.

3.3 Haptic Effects

To enhance the interactivity, the maps contained haptic effects. For low vision users, who did not rely on the touch tablet, different types of vibrations were associated with map features. The user required a haptic device [4] , to take advantage of the effects.

illustration_3.png

Figure 3: The user interacts with the haptic device

4. SVG Maps Creation

The project experimented with a few methods to generate interactive SVG maps. The method that we settled on was to use maps created with Adobe Illustrator and to add haptic effects through JavaScript. The maps were then exported as SVG. The SVG code was edited directly to add the sound effects. Another method we tried was to open maps from existing databases in a GIS, export them into SVG format, and add the interactive features in a text editor.

4.1 Methodology

The methodology was compatible with the following file formats: CorelDraw, Adobe Illustrator, Macromedia Freehand, SVGMapMaker SVG files.

  1. Apply Common Visual Standard

    There are cartographic conventions that apply to maps for people with visual impairment [TATHAM 1991] . We designed a template that dictated the position of elements in the header section (title, scale, and north arrow). The main concern was to ensure the maps had a consistent look.

    vancouver.png
    Example of a city approach map
  2. Organize Objects in Layers for Interactivity

    The second step in the methodology was to group all the elements in appropriate layers and label both elements and layers. All elements affected by the interactivity had to be grouped. This was done in Illustrator using the layers palette. This created a group tag in the SVG document. Each element that was later identified by the screen reader had to be given a label. This label was what the screen reader spoke out loud. We grouped the symbols for train station, bus station, and airport together. Primary, secondary and tertiary roads formed another group. Mountains and bodies of water formed two more groups.
  3. Assign Haptic Effects

    The third step was to assign JavaScript functions to layers. Each haptic effect was paired with a sound effect. We hoped this would make map features stand out more to people with visual impairment. Each category of map element was assigned a separate haptic effect via JavaScript; one for roads, one for built-up areas, one for water and occasionally one for borders. using the interactivity palette in Illustrator, the JavaScript functions to drive the events, were added. This tool added the code and the event in the SVG document. The code could have been added with a text editor.
  4. Assign Sound Effect

    The final step was to link in pre-recorded sound effects. By using the Adobe SVG Viewer implementation for audio, we were able to play a recorded sound when mouseover or mouseout occurred on a map feature.

4.2 System Requirements

The minimum system requirements are:

4.3 Coding the Interactive Features

4.3.1 Voice Annotation

The label of the feature that was clicked on was sent to the HTML page to be read by the text-to-speech software.

<g id="Haptic_Layers" onclick="OnClickEvent(evt)" . . .>
	<g id="Water" . . . >
		<path id="Strait_of_Georgia" . . ./>
					

NOTE: To view the OnClickEvent code Appendix1.html#onclickevent

4.3.2 Haptic Effects

Event functions were added to layers to provide the haptic effects.

<g id="Haptic_Layers"  onclick="OnClickEvent(evt)" . . . >
	<g id="Water" onmouseover="OnMouseover(evt, 'Spring')" onmouseout="OnMouseout(evt, 'Spring')" . . . >

NOTE: To view the OnMouseover code Appendix1.html#onmouseoverevent

To view the OnMouseout code Appendix1.html#onmouseoutevent

4.3.3 Sound Effects

Recorded sounds are played using the audio implementation of the Adobe SVG viewer.

<a:audio xlink:href="\water.wav" begin="Waters.mouseover"/>
<a:audio xlink:href="\water.wav" begin="Waters.mouseout"/>

5. User's Feedback

The publication of and access to tactile maps on the Internet was a very recent development. The first version of the MVI web site was officially launched in October 2002. For the hardcopy production of the Tactile Atlas of Canada, which is available in a downloadable format on the web site, extensive user testing was conducted. Students, teachers and mobility training instructors tested both the raised ink maps and capsule paper tactile maps. The maps published on the MVI web site follow the international guidelines recommended by the International Cartographic Association Commission on Maps and Graphics for Blind and Visually Impaired People.

Feedback was also solicited from cartographic professionals working in the field of tactile maps and graphics. The maps for the Thematic Tactile Atlas of Canada were also tested at W. Ross Macdonald, the largest residential school for blind and visually impaired students in Canada. This user centric approach resulted in development of high quality maps, which will serve blind and visually impaired users well. The Tactile Atlas of Canada received high praise from users and the professional cartographic community and was selected for national and international exhibitions by the Canadian National Cartographic Committee.

For the audio-tactile maps published on the Internet, we have received little feedback so far. The MVI web site passed the Web Accessibility Test (WAT) last September. However the site was still not widely publicized to the user community, mainly because of the need for specialized equipment and because the audio-tactile and haptic interactive maps were still in the implementation stage. The development of these maps was conducted in close cooperation with the user community, specially the section containing maps for mobility training. An extensive user testing stage is planned for next year for audio-tactile-haptic maps within the Web-4-All program at Industry Canada. The equipment necessary to interact with the audio-tactile maps has already been purchased and will be placed in the six Web-4-All Community Access Program sites. Further, each section of the MVI web site has a user corner, which will permit the project team to receive continuous feedback from the user community.

6. Conclusions and Future Directions

Emergence of the SVG format has made possible the efficient creation of digital maps that persons with visual impairment can use. The accessibility of these maps for the blind needs additional testing. The role of the SVG format in our project was to create powerful information-rich interactive maps. Our solution combined online SVG maps with printed tactile maps that the user can touch and feel.

We used several features of SVG to create interactive tactile maps. The open source nature of SVG will allow people to use this technology. The SVG documents can be adapted to other devices used by the visually impaired community.

Much progress has been made but much more work remains in terms of publishing and reading audio-tactile maps. There is a need for additional research in the area of the human-computer interaction. The implementation of Aural Style Sheets [5] in browsers as well as the integration of VoiceXML [6] will be a significant stage in assisting vision impaired persons to obtain geospatial information. But the good news is that maps on the Internet for persons with visual impairment are now a reality.

Footnotes

  1. Haptic

    Pronunciation
    'hap-tik
    Function
    adjective
    Etymology:
    International Scientific Vocabulary, from Greek: haptesthai, to touch
    Meaning
    Relating to or based on the sense of touch.

  2. Touch Tablet: The touch tablet used in this project was actually a touch screen designed as a monitor add-on that could be laid flat and used as a map reading device.

  3. Thermal enhancer: The thermal enhancer takes a map printed on swell paper and by applying heat, raises the ink to make a tactile map.

  4. Haptic device: Two-dimensional haptic devices can be used to aid computer users who are visually impaired by providing a slight resistance at the edges of windows and buttons so that the user can "feel" the Graphical User Interface (GUI). This technology can also provide resistance to textures in computer images which enables computer users to "feel" pictures such as maps and drawings.

  5. Aural Style Sheets were not considered in this project. However, to enhance the understanding of the maps, this could be implemented, depending on the browser's capability to follow the HTML 4.1 recommendation.

  6. At the time of writing this document (May 1st, 2003), Voice Extensible Markup Language (VoiceXML) Version 2.0 has the status of candidate recommendation. We hope the implementation of VoiceXML in browsers will bring a new dimension of interactivity through its use in future SVG maps for people with visual impairment.

Acknowledgements

I would like to thank the SVG community (W3C, and people who are spending free time, and sharing code) for the efforts done to create and improve open source accessible formats.

A special "thank you" to Dany, who gave me the time and the opportunity to present this paper.

Bibliography

[SIEKIERSKA, 2001 ]
Tactile Mapping Project at Canadian Federal Mapping Agency - Mapping Services Branch Siekierska E. et al., 2001. Published in Proceedings of the 20th International Cartographic Conference, Mapping the 21st Century, ICC 2001 Beijing, China, August 6-10, 2001, pp.: 2932-2942.
[TATHAM 1991]
The Design of Tactile Maps: Theoretical and Practical Considerations in Rybaczuk, K. and Blakemore, M., 1991, Tatham A. F., 1991: Mapping the nations : Proceedings of the 15th International Cartographic Conference, Vol. 1, London, ICA, pp. 157-166.
[TATHAM 2001]
Achievable Goal or Chimera? Standardization in Tactile Mapping Tatham A. F., 2001. Published in Proceedings of the 20th International Cartographic Conference, Mapping the 21st Century, ICC 2001 Beijing, China, August 6-10, 2001, pp.: 2923.
[Aural Style Sheet in CSS2]
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[Adobe Developer pages]
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[Web-4-All site]
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Copyright 1999-2000, last accessed: 2003-05-29 http://www.w3.org/TR/SVG-access/
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Updated: 2003-02-31, last accessed: 2003-05-29 http://tactile.nrcan.gc.ca
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Scalable Vector Graphics (SVG) 1.1 Specification W3C Recommendation 14 January 2003 http://www.w3.org/TR/SVG11/

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