I gave a presentation today on how we can create web mapping applications that address accessibility guidelines.  I’m not sure if I can share the slides, as they are EC branded…but I think I can share the transcript of the presentation to anyone who is interested:

Slide: Title

Web Mapping Accessibility and CLF 2.0

Alecia Fowler

Environment Canada

February 2011

Slide: Introduction

During this presentation I will discuss what steps we can take to create accessible web mapping applications.  I’ll talk about why it is not a clear cut case and where the grey areas are.  We have been able to identify some solutions but there are still gaps so please feel free to ask questions or bring up any ideas.

Slide: CLF 2.0

The goal of CLF 2.0 is to created uniform, accessible web content with a departmental branding

The Federal Governments stance on Accessibility is stated in Treasury Boards Common Look and Feel for the Internet 2.0: http://www.tbs-sct.gc.ca/clf2-nsi2/index-eng.asp

The standard is comprised of 4 parts:

From a web mapping point of view we are concerned with Part 2 and Part 3, I will cover Part 3 the Standard on Common Web Page Formats first as it is a bit more straightforward.

Slide: Standard on Common Web Page Formats

This part of the standard covers the layout and formatting of web pages.  The design is further expanded on to reflect department specific branding though Environment Canada’s E-Communications department.  They have a design guide which stipulates the usage, style and colour of various page features.  This guide is useful for static pages but when it comes to dynamic web applications there are more unknowns.

EC Internet Look and Feel Guide http://intranet.ec.gc.ca/communications/default.asp?lang=En&n=243D8F0F-1

We have recently finished a project for the Communications branch.  As they are responsible for web content consistency it is a safe bet to model your web mapping content after them.

The application was built with two interfaces.  One that fits nicely into the CLF template and looks similar to all other EC pages, and one that looks more like mainstream web mapping applications:

Map of EcoAction Funded Projects

http://maps-cartes.ec.gc.ca/ecogeo/

Slide: Standard on Accessibility, Interoperability and Usability of Web sites

Satisfying Part 2 of the CLF standard is not as simple as it deals with web accessibility.

  • The goal of web accessibility is to ensure that content online is available to all people regardless of disability.
  • Most of the information in a web mapping application is found in the map which can only be accessed visually.
  • Due to its high dependence on vision, other accessibility requirements often get overlooked

Slide: W3C WCAG Checkpoints

The CLF standard requires web content to satisfy the Priority 1 and 2 checkpoints of the W3C’s Web Content Accessibility Guidelines which are divided into 4 categories to ensure you content is perceivable, operable, understandable, and robust.

  • Perceivable
    • Provide text alternatives for non-text content.
    • Provide captions and alternatives for audio and video content.
    • Make content adaptable; and make it available to assistive technologies.
    • Use sufficient contrast to make things easy to see and hear.
  • Operable
    • Make all functionality keyboard accessible.
    • Give users enough time to read and use content.
    • Do not use content that causes seizures.
    • Help users navigate and find content.
  • Understandable
    • Make text readable and understandable.
    • Make content appear and operate in predictable ways.
    • Help users avoid and correct mistakes.
  • Robust
    • Maximize compatibility with current and future technologies

But some of these priorities don’t affect web-mapping applications, so we’re just going to concentrate on the ones that do.

  • Perceivable: Provide text alternatives for non-text content.
  • Perceivable: Make content adaptable; and make it available to assistive technologies.
  • Perceivable: Use sufficient contrast to make things easy to see and hear.
  • Operable: Make all functionality keyboard accessible.
  • Understandable: Make text readable and understandable.
  • Robust: Maximize compatibility with current and future technologies

Slide: W3C WCAG Checkpoints

Make content adaptable; and make it available to assistive technologies.

  • Offering information in multiple formats
    • The life of a web mapping application is the data, so please offer a text-based version of the data you are loading into the map
  • Allow your users to download it themselves
  • Display it in charts, tables, and graphs etc.
  • Have the most accessible version of your site as the first format encountered by a visitor

Example: National Pollutant Release Inventory (NPRI)

http://www.ec.gc.ca/inrp-npri/default.asp

  • Online data
  • Online maps
  • Downloadable map layers for Google Earth (.kmz)
  • Downloadable data for Microsoft Access (.mdb)
  • Download data for Microsoft Excel (.xls)

Slide: W3C WCAG Checkpoints

Use sufficient contrast to make things easy to see and hear.

This checkpoint has to do with the cartography of the map.  The design should take into account any colour blindness or weak vision of the user.  This could be text size or colour choice for symbology.

Slide: W3C WCAG Checkpoints

Make all functionality keyboard accessible.

Your web mapping application should not rely solely on the mouse for access to any feature or information

  • Map Tips
  • Point Selection
  • Map Navigation

This is common for web mapping applications as much of the information and features are embedded into the map.

Slide: W3C WCAG Checkpoints

Make text readable and understandable.

  • The advantage of using maps to convey spatial data is that they allow for an easier understanding of spatial relationships and patterns
  • If the alternate to a map is access to the data in raw format it should be laid out in an understandable way not just a data dump

Slide: W3C WCAG Checkpoints

Maximize compatibility with current and future technologies

In order to do this we recommend Progressive Enhancement as a design approach to any web page.

Helpful Links:

http://en.wikipedia.org/wiki/Progressive_enhancement

http://www.alistapart.com/articles/understandingprogressiveenhancement/

Slide: Web Mapping Accessibility Template (WMAT)

The Inter-Agency Committee on Geomatics (IACG) Web Mapping and Accessibility Sub-group is comprised of subject matter experts from various departments across the federal government.  It is our goal to create a best practices guide for the community.  WMAT is a demo that we will be using to show how these best practices are put into play.  We are hoping it will encourage communication throughout the departments and encourage feedback on how to make an accessible application usable.

We will be releasing an updated version that will have widgets for various web mapping components that developers will be able to use on their own sites.

Associated Links

IACG Sub-Group: http://www.gcpedia.gc.ca/wiki/Inter_Agency_Committee_on_Geomatics/Web_Mapping_and_Accessibility

WMAT: http://maps-cartes.ec.gc.ca/wmat/

Slide: W3C WCAG Checkpoints

There is one outstanding checkpoint:

Provide text alternatives for non-text content.

I’ve saved this for the end as this is the most complicated checkpoint, and one we have yet to have a solution for.  The map is non-text content.  To satisfy this checkpoint we need to describe the map in a meaningful, comparable way to the understanding a person takes away from viewing the map.

Consider:

  • The amount of data behind building a map image.  The number of layers, and how each of those layers represented and interact with each other.
  • The different types of maps there are.  Does map type affect a description?
  • An interactive web mapping application, every time the extent changes or the layers change.  Should the description then also be updated?

Slide: “Describing a Thematic Map”

I chose to delve a little deeper into this area for my research as it was out of scope for anything we could answer as a web mapping development team.

My research question was: How does a sighted person describe a thematic map?

I was hoping to find a way to form meaningful text descriptions of a thematic map that would not just be useful to visually impaired users, but potentially sighted users as well.

I conducted a study where I asked members of the sighted community to describe various thematic maps.

Slide: Database of words

I then took the resulting data and tagged what I thought to be as keywords in the descriptions.

Slide: Categories

I further divided the keywords into categories and sub-categories by looking at how they were used in the descriptions and what they were meaning to convey.

  • Directional
  • Topographical
  • Quantitative
  • Shape
  • Landmark
  • Query Data
  • Thematic
  • Size
  • Jurisdiction
  • Colour
  • Distance
  • Location

Slide: Proposed Description Framework

My study resulted in the following proposed framework in how to structure a description of a thematic map:

A description of a thematic map should relay context by providing

  • Query data, for a general understanding of what the map is representing;
  • Jurisdiction, for a specific area the map is covering;
  • Location, to give real-life names to the area of jurisdiction;

The points shown in the thematic layer should be described in relation to the various topographical features and landmarks by specifying:

  • Size
  • Distance
  • Direction
  • Placement

These descriptions are enriched through the use of descriptive words of the various layers and their features, which should relay

  • Shape
  • Size
  • Colour
  • Direction
  • Quantity

Slide: Example

This map is showing locations of facilities which reported pollutant releases in Canada in 2008. There is a town named Springfield, which is based along the east bank of a river. The river runs alongside the town from north to south. Approximately half way down, the river is joined by a smaller river that arches from the left. At the point where the two rivers join is a railway track. There are 3 facilities shown, the first is at the terminus of the railway track. The second point is located at the south end of the town and to the east of the first point. There is a small park near the center of town and bordering the east side of the river, as well as an orange symbol over the river about X km north of the park. The third point is due east of these two features, and is just outside the north-east side of the town.

Slide: Resources

Common Look and Feel for the Internet 2.0

http://www.tbs-sct.gc.ca/clf2-nsi2/index-eng.asp

CLF 2.0 Part 2: Standard on the Accessibility, Interoperability and Usability of Web Sites

http://www.tbs-sct.gc.ca/clf2-nsi2/clfs-nnsi/clfs-nnsi-2-eng.asp

CLF 2.0 Part 3: Standard on Common Web Page Formats

http://www.tbs-sct.gc.ca/clf2-nsi2/clfs-nnsi/clfs-nnsi-3-eng.asp

EC Internet Look and Feel Guide http://intranet.ec.gc.ca/communications/default.asp?lang=En&n=243D8F0F-1

Map of EcoAction Funded Projects

http://maps-cartes.ec.gc.ca/ecogeo/

National Pollutant Release Inventory

http://www.ec.gc.ca/inrp-npri/default.asp

Progressive Enhancement:

http://en.wikipedia.org/wiki/Progressive_enhancement

http://www.alistapart.com/articles/understandingprogressiveenhancement/

About these ads