frastlin
commented
2 months ago Here are passing non-visual map examples, let me know if you'd like some examples of failing maps as well:
Detailed Text Description
Although this level of text description is rare, let’s try and hit all the elements of spatial knowledge for a few states:
- Washington State is distinguished by its unique geographical shape, featuring a notable Olympic Peninsula extending around 25 miles into the Pacific Ocean on the northwestern corner and a more rectangular eastern region. The state is oriented with the Pacific to its west, Canada to the north, Idaho to the east, and Oregon to the south, making it the 18th largest state in the U.S. It is 360 miles wide from east to west and 240 miles long. The southern border between Washington and Oregon is primarily defined by the Columbia River, making it fairly straight but with natural deviations due to the river's course. There is a notable 100 mile wide "hump" or bulge in this border, where Washington's territory extends southward 15 miles into what would otherwise be a straight line, near the mid-eastern area around Walla Walla. The eastern border with Idaho is largely straight from north to south. The northern border with Canada is a straight line. The western border is the most irregular, defined by the Pacific coastline to the west and the Puget Sound to the northwest. The Olympic Peninsula juts out around 25 miles into the Pacific Ocean in the middle of the border around 190 miles south of the northern border, creating a varied and rugged coastline. The Puget Sound further indents the state's western boundary, with numerous inlets and islands creating a complex maritime boundary. Washington state has 1975382 Total Cases.
- Oregon is characterized by its diverse geographical features, with the rugged Pacific coastline defining its western edge and the more uniform eastern region bordered by Idaho. The state is situated with the Pacific Ocean to its west, Washington to the north, Idaho to the east, and California and Nevada to the south, ranking as the 9th largest state in the U.S. Oregon spans about 360 miles from east to west and approximately 260 miles from north to south. The northern border between Washington and Oregon is primarily defined by the Columbia River, making it fairly straight but with natural deviations due to the river's course. There is a notable 100 mile long "hump" or bulge in this border, where Washington's territory extends southward around 15 miles into what would otherwise be a straight line, near the mid-eastern area around Walla Walla. The eastern border between Oregon and Idaho is relatively strait with a small hump of Idaho that goes into Oregon around the middle of the border between Nevada and Washington. The southern border is relatively straight, with minor deviations. It is defined by surveyed lines rather than natural features, creating a clear demarcation between Oregon and its southern neighbors, California and Nevada. California extends from the pacific ocean and covers about 60% of the southern border, and Nevada covers the eastern part of the southern border for around 40%. Oregon's western border is marked by its Pacific coastline, which stretches approximately 363 miles. Unlike the relatively straight borders to the north and south, the western coastline adds a natural and irregular edge to the state's shape with a slight slant, around 25 miles, into the pacific ocean near the southern edge. Oregon has 974924 Total Cases.
- Idaho is marked by its distinctive shape and diverse geography, featuring a narrow panhandle that stretches northward, flanked by Washington and Montana, and a broader southern section that shares borders with Utah, Nevada, Oregon, and Wyoming. The state is oriented with Canada to its north, Montana and Wyoming to the east, Nevada and Utah to the south, and Oregon and Washington to the west, ranking as the 14th largest state in the U.S. Idaho spans about 305 miles from north to south and approximately 479 miles from east to west at its widest point. Idaho's northern border is relatively short, about 40 miles, confined to the narrow panhandle, and is defined by a straight line that separates it from British Columbia, Canada. The eastern border with Montana and Wyoming starts in the north with Montana. For around 100 miles, the border is fairly strait going north to south with a very gentle slope east. A stronger eastern curve into Montana happens, and Idaho eventually has Montana completely to the north for about 150 miles until it reaches Wyoming. The eastern border between Idaho and Wyoming is strait for around 100 miles. The southern border is strait for around 479 miles (its widest point). The southern border is split equally between Utah in the east and Nevada in the west. The eastern border between Oregon and Washington is strait for around 305 miles, and 60% in the south is the border with Origan and the 40% in the north is with Washington. Idaho has 525825 Total Cases.
- …
- Oregon, Washington and Idaho are three states with Washington and Oregon on top of one another, and sandwiched between the pacific ocean on the west, and Idaho in the east.
Evaluation of Detailed Text Description
- Spatial knowledge: All elements of landmark knowledge are present, including name, type, shape, orientation, and size of the different features. Although the border descriptions could be more detailed, the route around the border is described enough to get basic distance, direction, legs of the route, and shape of the route. Each of the features has a detailed description, and there is a broader description of the features after the end. All elements of distance, direction, shape, size, orientation, and general layout are described. This description has about a 20 mile fidelity error, and the curve in Idaho could be described more accurately.
- Numeric values: All the numeric values are present, assuming the user can switch between the desired values, or that there is a longer list of values at the end of each state’s description.
- Verdict: Pass with caveats. This map would exclude users who desire to record exact shapes and contours of the map. It has about a 20 mile margin of error, so is still not as accurate as most maps with around 60 feet margin of error. So as long as the presented visual map has a 20 mile margin of error, this is WCAG compliant.
Interactive Alt-Text
Here is an Audiom map of COVID Cases over the U.S. showing interactive alternate text. Here is a video showing the Audiom interactive alternate text usage.
Evaluation of Interactive Alt-Text
- Spatial Knowledge: All elements of landmark knowledge are present, including name, type, shape, orientation, and size of the different features. By weaving in and out of the borders, the route around the border includes exact distance, direction, legs of the route, and shape of the route. All survey knowledge elements for each point, polygon, and line, including distance, direction, shape, size, orientation, and general layout are accessible. The fidelity is as small as the provided dataset.
- Numeric values: All numeric values for all features are present.
- Verdict: Pass! Although one could argue the shapes are a little grid-like, the step size can be reduced, and work is being done to make a way to have the shapes be more clear.
Here is a video requiring headphones showing a campus map with interactive alternate text as well.
KMSOC
goodwitch
Overview
Currently, digital geographic maps are evaluated using section 6. Images, but digital geographic maps are too complicated to be combined under images without explicit evaluation criteria. Digital geographic maps are complex multicomponent elements that require an entire evaluation of their own, above the general website evaluation. In particular, WCAG 1.1:Non-text content requires a more nuanced definition. Having requirements specific to digital geographic maps will reduce ambiguity of what to evaluate on geographic maps, and ensure evaluation criteria are clear and consistent across results so that the section 508 standards are applied correctly to this complex component.
An Accessibility Conformance Report was done on the top 11 digital map tools, and the below criteria are the most common failures.
Section 1.1.1:Non-Text Content Applied to Maps
Section 1.1.1:Non-Text Content states: “All non-text content that is presented to the user has a text alternative that serves the equivalent purpose”. The problem is that “equivalent purpose” is somewhat ambiguous and is often misinterpreted. In academic literature the framework of landmark, route, and survey knowledge acquisition is used, and that is what I propose be the refined framework for section 1.1.1:Non-Text Content applied to digital geographic maps.
Traditionally, the practice of making maps accessible is to step back and look at the “point” of the map. Is the alternative that’s presented conveying the primary objective of the map? This practice can be observed by blog posts written by prominent digital accessibility experts and documentation by government agencies: https://www.tpgi.com/accessible-digital-map-experiences/ https://mn.gov/mnit/about-mnit/accessibility/maps/static.jsp https://github.com/DEFRA/design-standards/blob/master/Maps.md
This practice is not compliant with section 1.1.1, as following this method only has the “main purpose” conveyed when the criteria states “equivalent purpose”. If the “main purpose” of a university campus map is to show roads on campus, it does not help the map user needing to manage garbage cans on campus. A visual campus map would have garbage cans, but since they’re not the “main purpose”, the map user accessing the text alternative would not be able to use the map for the “equivalent purpose” that the original map could have been used for. Using the survey knowledge framework would facilitate this “equivalent purpose” though.
Siegel et al. published a seminal work in 1975, titled “The development of spatial representations of large-scale environments” defining the framework of landmark, route, and survey knowledge for evaluating spatial knowledge acquisition from geographic maps. This framework has subsequently been used in numerous studies across maps in visual, auditory, and tactile modalities including: https://cartographicperspectives.org/index.php/journal/article/view/cp75-ishikawa-takahashi/html https://www.tandfonline.com/doi/full/10.1080/13875868.2021.1969401?casa_tok https://www.sciencedirect.com/science/article/pii/S0272494407000734 https://icad2022.icad.org/wp-content/uploads/2022/06/ICAD2022_27.pdf https://www.frontiersin.org/articles/10.3389/fnhum.2014.00223/full https://www.sciencedirect.com/science/article/pii/S0272494406000594
This framework is rigorous, quantifiable, and easy to use.
Definitions and criteria to evaluate each element of landmark, route, and survey knowledge:
Using this framework of spatial knowledge allows a quantitative evaluation of the spatial information in a map. Additionally, there needs to be full access to the numeric or other information that may be overlayed on the geographic features. If a text alternative is missing any of these elements, it does not serve the “equivalent purpose” of a map, and is not section 508 compliant.
Section 1.4.11:Non-text Contrast Applied to Maps
1.4.11:Non-text Contrast states: “The visual presentation of the following have a contrast ratio of at least 3:1 against adjacent color(s): User Interface Components; Visual information required to identify user interface components and states, except for inactive components or where the appearance of the component is determined by the user agent and not modified by the author; Graphical Objects; Parts of graphics required to understand the content, except when a particular presentation of graphics is essential to the information being conveyed.” Unfortunately, for thematic maps showing more than 3 categories of colors, it’s physically impossible to comply with this criteria as written. Recommended compliance criteria should be as high of contrast as possible color scheme, coupled with patterns to distinguish between the values. The pattern criteria works for colorblind users, and the high contrast colors work for low-vision users.
Section 2.1.1 Keyboard Applied to a Map
Section 2.1.1 Keyboard states: “All functionality of the content is operable through a keyboard interface without requiring specific timings for individual keystrokes, except where the underlying function requires input that depends on the path of the user's movement and not just the endpoints.” This includes keyboard accessibility for all features (e.g., points, polygons, and lines) on the map. For map creation tools, drawing with the mouse or touchscreen may be dependent on a path of the user’s movement, but it’s possible to place points and vertices with the keyboard.
Proposed Content for Section 508 ICT Testing Baseline: 25. Geographic Maps
Accessibility Requirements
Test Method Rationale
Limitations, Assumptions, Exceptions
25.A Test Procedure for Maps
Baseline Test ID: 25.A-Maps
Identify Content
Identify a collection of points, polygons, and lines and possible associated controls that comprise a map, whether it’s an image, interactive, in a document, and or in an iFrame.
Test Instructions
Test Results
If any of the above checks fail, then Baseline Test 25.A- Maps fails.
Advisory: Tips for streamlined test processes
WCAG 2.2 Techniques
The following sufficient techniques and/or common failures were considered when developing this test procedure for this baseline requirement: