ICTTestingBaseline Adding Testing Criteria Specific to Digital Geographic Maps

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:

Landmark, which is the sensory characteristics, name, type, shape, orientation, and size of a particular feature or location on the map;
Route, how two landmarks connect including distance, direction, legs of the route, and shape of the route;
Survey, which is the overall understanding of how all the points, polygons, and lines relate through their distance, direction, shape, size, orientation, and most importantly, general layout on the map.

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 without employing creative solutions. The following two options can be used:

Oreo borders. Instead of having map category colors touch each other directly, the Oreo method is a triple line outline where the feature border is a black outline (black cookie) surrounded by a white outline ( white frosting), surrounded by a 2nd black outline (2nd black cookie). With the Oreo cookie technique, you can distinguish any feature category color at 3 to 1, because you controlled the background. If black doesn't work as the cookie layer, you could flip it to white cookie, black frosting, white cookie.
Patterns to distinguish between the category values instead of colors.

No matter the choice, there needs to be an as high of contrast as possible color scheme, as low vision users dislike patterns. They are also unable to tell apart colors that have a low contrast ratio. Additionally, text labels with the values need to be provided.

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

Section 1.1.1:Non-Text Content - All non-text content that is presented to the user has a text alternative that serves the equivalent purpose, except for [specific] situations.
Section 1.3.1:Info and Relationships - Information, structure, and relationships conveyed through presentation can be programmatically determined or are available in text.
Section 1.4.3 Contrast (Minimum) - The visual presentation of text and images of text has a contrast ratio of at least 4.5:1, except for the following: Large Text; Large-scale text and images of large-scale text have a contrast ratio of at least 3:1; Incidental; Text or images of text that are part of an inactive user interface component, that are pure decoration, that are not visible to anyone, or that are part of a picture that contains significant other visual content, have no contrast requirement. Logotypes; Text that is part of a logo or brand name has no contrast requirement.
Section 1.4.11:Non-text Contrast - 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.
Section 2.1.1 Keyboard - 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.
Section 2.4.7 - Any keyboard operable user interface has a mode of operation where the keyboard focus indicator is visible.
Section 3.1.2 Language of Parts - The human language of each passage or phrase in the content can be programmatically determined except for proper names, technical terms, words of indeterminate language, and words or phrases that have become part of the vernacular of the immediately surrounding text.
Section 4.1.2 Name, Role, Value - For all user interface components (including but not limited to: form elements, links and components generated by scripts), the name and role can be programmatically determined; states, properties, and values that can be set by the user can be programmatically set; and notification of changes to these items is available to user agents, including assistive technologies.

Test Method Rationale

These tests use spatial knowledge as a quantitative framework for evaluating “equivalent purpose” as other methods (e.g., identifying the “main purpose”) are inherently unequal. Spatial knowledge is comprised of landmark, route, and survey knowledge: Landmark, which is the sensory characteristics, name, type, shape, orientation, and size of a particular feature (e.g., point, polygon, or line) or location on the map; Route, how two landmarks (e.g., points, polygons, or lines) connect including distance, direction, legs of the route, and shape of the route; and Survey, which is the overall understanding of how all the features (e.g., points, polygons, and lines) relate through their distance, direction, shape, size, orientation, and most importantly, general layout on the map.
The tests expect 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.
The map is comprised of the viewing area and controls around the viewing area.

Limitations, Assumptions, Exceptions

For thematic maps showing more than 3 categories of colors, it’s physically impossible to comply with [SC 1.4.11] without employing creative solutions. The following two options can be used:
1. Oreo borders. Instead of having map category colors touch each other directly, the Oreo method is a triple line outline where the feature border is a black outline (black cookie) surrounded by a white outline ( white frosting), surrounded by a 2nd black outline (2nd black cookie). With the Oreo cookie technique, you can distinguish any feature category color at 3 to 1, because you controlled the background. If black doesn't work as the cookie layer, you could flip it to white cookie, black frosting, white cookie.
2. Patterns to distinguish between the category values instead of colors.
No matter the choice, there needs to be an as high of contrast as possible color scheme, as low vision users dislike patterns. They are also unable to tell apart colors that have a low contrast ratio. Additionally, text labels with the values need to be provided.
For documents that are unable to show alternatives, a link to an accessible alternative is required.
This test evaluates the most common failures with maps, but other failures are possible, so the map elements should be evaluated along with other aspects of the website.

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

Check that the following are true [SC 1.1.1]: a. It’s possible to identify the sensory characteristics, name, type, shape, orientation, and size of all features (e.g., points, polygons, and lines) on the map through text. b. It’s possible to understand the distance, direction, legs of the route, and shape of the route between any two or more features (e.g., points, polygons, and lines) on the map. c. It’s possible to obtain the distance, direction, shape, size, orientation, and general layout of and between all features (e.g., points, polygons, and lines) on the map. d. All numeric values (if the map contains numeric values) are accessible and connected to all the features (e.g., points, polygons, and lines) associated with the numeric values. e. Logos have alt-text in the “alt” attribute. f. Icons (e.g., “open map in new window”, zoom in, zoom out, close, copyright, etc.) have text labels or an “alt” attribute with text describing the functionality of the control. g. Decorative images or text are hidden from screen readers with aria-hidden.
Verify that information (such as a control's state), structure, and relationships conveyed through presentation can be programmatically determined or are available in text [SC 1.3.1]. Look for the following: a. There’s a “disabled” attribute on the buttons that can be disabled (e.g., zoom, or reset orientation). b. There’s an aria-pressed attribute on the buttons that can be activated or deactivated (e.g., locate me, and full screen). c. The entire map is wrapped in a labeled region landmark so screen readers and other assistive technology know what is in that area. d. The Scale bars/rulers are understandable non-visually, or they are hidden from the screen reader. e. For thematic maps, all numeric values and ranges are accessible to a screen reader and comprehensibly associated with their related features (e.g., points, polygons, and lines). f. All feature properties (e.g., name, type, information card) are possible to activate in the text and other modal versions of the map. g. Spatial relationships (e.g., route and survey knowledge) can be ascertained through text.
Verify that the visual presentation of text and images of text has a contrast ratio of at least 4.5:1 [SC 1.4.3], except for the following: a. Large Text: Large-scale text and images of large-scale text have a contrast ratio of at least 3:1; b. Incidental: Text or images of text that are part of an inactive user interface component, that are pure decoration, that are not visible to anyone, or that are part of a picture that contains significant other visual content, have no contrast requirement
If there are more than three discrete ranges being represented and it’s impossible to meet [SC 1.4.11] with a solid color border, either an Oreo border and or patterns are provided as an optional alternative. Additionally, as high of contrast as possible between colors is maintained.
Ensure all map functionality can be accessed using only a keyboard [2.1.1]. Look for the following: a. The map display is pannable using the keyboard. b. Map controls and information are possible to access without using hover with the mouse. c. Drag and drop controls can be operated via the keyboard. d. All features (e.g., points, polygons, and lines) can be focused using a keyboard (preferably not just through tab.) e. If there is map creation, points, polygons, and lines can be created anywhere on the map using the keyboard.
Check all the following are true [SC 2.4.7]: a. It’s possible to sequentially navigate all components using the tab key (and operate all controls). b. Check that scripts are not used to remove focus and that each component is highlighted with a visible focus outline.
The lang attribute is set on all webpage and iFrame components, and the specified language code matches the language of the content (which may change due to language negotiation, based on system settings) [SC 3.1.2].
For all user interface components, look for the following [SC 4.1.2]: a. The name and role can be programmatically determined, including for the map itself, any parent iFrame, controls all have an accessible name, and controls have the correct role; b. States, properties, and values that can be set by the user can be programmatically set; b. and notification of changes to these items is available to user agents, including assistive technologies. c. If the map is embedded in a document that does not have an alternative version, there is a link to a Conforming Alternate Version.

Test Results

If any of the above checks fail, then Baseline Test 25.A- Maps fails.

Advisory: Tips for streamlined test processes

Automated accessibility tools such as AXE can help with identifying several of the test criteria (e.g., contrast), but most functionality will need to be determined through manual testing.
Content that uses color must have an additional visual cue (e.g., patterns). Instructions that rely on a sensory characteristic must have a non-sensory cue.

WCAG 2.2 Techniques

The following sufficient techniques and/or common failures were considered when developing this test procedure for this baseline requirement:

Apr 19 '24 13:04 frastlin

Here is a blog post with both passing and non-passing alternate text descriptions. Some of the passing options are below:

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.

MUD Text Interface

Using an open source MUD engine, one can combine detailed text descriptions with an interactive element. Example is coming soon.

Evaluation of a MUD Text Interface

Spatial Knowledge: All elements of landmark knowledge are present, including name, type, shape, orientation, and size of the different features that can be found in the feature description. The room description contains the size of the area, and each feature contains its own size. Since the user is able to move between features, or move a specified distance (depending on how the designer lays out the interface), it’s possible to understand how two landmarks connect including distance, direction, legs of the route, and shape of the route. It’s also possible to understand the distance, direction, shape, size, orientation, and general layout of all points, polygons, and lines by combining reading the text descriptions with moving through the interface.
Numeric values: All numeric values for all features are present.
Verdict: Pass! Although almost all aspects need to be described for features that are smaller than a room, or that are combined in a room, it’s possible to understand route and survey information between larger features by moving through the interface. The author needs to be conscientious of fidelity as well.

Apr 29 '24 18:04 frastlin

If we are solely limiting discussion to what we should required in alt text for maps, below are several thoughts:

Alt text should follow the guiding principle for any image: If I removed the map and just had the information in the document and the alt text, would all the critical information being communicated by that map still be fully available? What critical information would I lose if I couldn’t perceive the map? If there is information loss without the image, there may be more work to do to ensure that the map is accessible to everyone.

Our challenge is still related to complex maps that are meant to be exploratory or navigational. In these cases, I would suggest attempting to understand the author's intention. If the author did not intend the map to be used in that way, it should be acceptable to have alt text that matches the author's intention (also understand that the tester may not be able to know the author's intention)

Where possible, an additional text alternative for all data and information is provided

This is more directly applicable in the case of maps that are visual representation of data tables (e.g., https://www.cdc.gov/wcms/4.0/cdc-wp/data-presentation/examples/example-us-map-counties.html)
This may not be sufficient for something such as a campus map/navigational map/exploratory map

Where a text alternative to full describe map content and context is not possible, include, if possible, an alternative means to access content such as a POC, link to google map, or other interactive means that will provide an accessible alternative

Understood that a POC may not always be an option nor reasonable option
Understood that a google map or other alternative map will not be available or possible
There are still gaps here as there may be many scenarios where it isn't possible to achieve any of the above. Does that mean that complex navigational maps will always fail until an accessible alternative is provided?

We also had a suggestion to split out minimum requirements based on the type of map. Some types of maps (in more plain language) are:

Data visualization maps (e.g., topographical, country, economic, weather, other data or theme-based representations)
- These most likely have data driving the visual representation and often can also express the data in accessible tables
Navigational maps (road maps, campus maps, maps used for directions and navigation)
- These map be simple or complex. Simple maps may be easily summarized in alt text. Complex maps include myriad starting and stopping points which are impossible to describe in entirety.
Property maps (often hand drawn due to land surveys)
- Specific to show land delineation and may be easily summarized in text format.
Historical maps
- Broad grouping of older maps where author's purpose may not even be able to be discerned. Text may also be faded/missing.

Jul 11 '24 17:07 KMSOC

Hello, The above response seems to reiterate the current best practice presented by places like the state of Minnesota. Current best practice is not systematic, quantitative, rigorous, reproducible, or evidence based. The current best practice is harmful to people depending on the alternate text for viewing maps because it is not an “equivalent” access to the content. Blind people are calling for these practices to be updated to something that can allow for professional blind cartographers to exist which the current best practice does not allow. The proposed test is quantitative, rigorous, reproducible, systematic, and based on decades of research in the cartographic community.

The guidance for 1.1.1 states “All non-text content that is presented to the user has a text alternative that serves the equivalent purpose”. WCAG does not mention “critical information”, it only mentions “equivalent purpose”. If the author is only providing “critical information”, that is an author interpretation that could lead to any kind of alternate text of any granularity. It’s very important that equality is not completely subjective. This is why this issue was created, because current alt-text for maps follows the practice of identifying the “purpose” or the “critical information” as identified by the author. This could lead to alt-text for the eclipse map of the lines of totality saying something like: “This map is of the lines of totality across the contiguous United States. The line of full totality begins at the southern border of Texis, goes northeast past both San Antonio and Austin, continues northeast to Dalis, then enters Oklahoma. The line of full totality covers the eastern edge of Oklahoma and the western edge of Arkansas, just missing Littlerock. The line then travels northeast, covering the central part of Missouri, then slight northeast into Illinois. In Illinois, the line of full totality goes east into Indiana and covers all but the southern edge of Indiana. The line of full totality then travels east into both Michigan and Ohio. The line then travels northeast into the northwestern edge of Pennsylvania, and into New York. The line of full totality passes over Buffalo, and east into Vermont. The line then goes northeast over the northwestern corner of New Hampshire and into Maine. The line then travels through the center of Maine, covering all but the very northern and very southern edges. The line of full totality then continues northeast.” This alt-text follows current best-practice, but it’s missing the majority of the information from the above map. It is not systematic in presenting including distance, shape, size, and general layout of the points and polygons. This alt-text is missing everything about the shapes, sizes, orientations, and distances of the state polygons, the exact locations of the city points and how far the city points are from the other states or city points, and there’s no information about the lines of 95% totality, 75% totality, or 50% totality. This alternate text fails to give the “equivalent purpose” to the visual map because it is missing all the above information. Using the interactive alt-text eclipse map I was able to write this text description, and I could have added all the missing detail. I’m completely blind. The above interactive alternate text map provides distance, direction, shape, size, orientation, and general layout of points, polygons, and lines. The above interactive alt-text map shows all lines of totality, as well as states without any lines of totality. The remainder of the comments assume it’s possible to fully convey geometries through alt-text. a. The “author’s intention” is different than the “equivalent purpose”. 1.1.1 doesn't mention an author’s “intention”. “intention” is subjective and is not “equivalent”. If the author did not intend to show geometries, they would have left them off the map, which means there is no longer a map and this test is not applicable.
“Where possible” is also not mentioned as an exception to 1.1.1. Section 1.1.1 states for “charts, diagrams, audio recordings, pictures, and animations, text alternatives can make the same information available in a form that can be rendered through any modality”. It is always possible to provide a text alternative to a map that follows these guidelines. If you can give me some examples of when alternate text following these guidelines is not possible, we can discuss those. a. This COVID statistic map from the CDC does not convey any distance, direction, shape, size, orientation, or general layout of points, polygons, or lines. True, the data table is overlaid on the geographic map, but the visualization has the geometries of the counties. This thematic map from the CDC overlays the data table content on the geometries visually, so the text alternative should have the geometries as well. Just looking at this table, can you answer “What county bordering “CA, Santa Clara” has the highest number of vaccinated people? No. Can you answer this question when looking at the visual map? Yes. This is a clear violation of 1.1.1. I don’t have an example of an interactive alt-text map showing counties, but here’s an interactive alt-text showing COVID statistics over the United states. Can you answer “What state bordering California has the highest number of cases per one million through text?” Yes, Arizona.
“possibility” is different than "equivalent purpose" mentioned in 1.1.1. It is possible to have a fully accessible alternative for any map.
Geometries are always critical to a map by definition. The entire definition of a map is that it’s a symbolic spatial representation. If geometries are removed, what’s left is a table. Removing geometries in the alt-text does not serve the "equivalent purpose" as the visual map that includes geometries, so does not meet 1.1.1. a. Data visualization maps: These maps have tabular data overlayed on them, but the reason why tabular data is overlayed on geometries is to convey spatial relationships between the geometries and spatial data. it's impossible to understand spatial relationships only using a simple table. Using a simple table, a scientist can't understand the spread of ice melt over the Atlantic ocean. b. Navigational maps: As mentioned previously, a “summary” is different than the “equivalent purpose”. When reading section 1.1.1, "summaries" are only mentioned in relation to a data chart. According to G95 “summaries” are only applicable when meeting 1.1.1. if they are “a short text alternative that briefly describes the non-text content. (A long text alternative is then provided using another technique such that the combination serves the same purpose and presents the same information as the original non-text content.)”. There needs to be a clear, systematic way of evaluating the longer alternate text that’s provided, and just saying “give a summary” is inadequate. The purpose of this issue is to clarify that “equivalent purpose” really means the spatial aspect of the map. Please provide an example map that’s “impossible to describe in entirety” and I’ll demonstrate how to do it. It’s possible to create alt-text that describes the entire spatial features of the U.S. down to the subatomic level. The difficulty is creating, indexing and easily understanding this information. The methods of interactive alt-text, MUD Text Interface, and Detailed Text Descriptions in post two are just three ways to do it. Additionally, a campus map is used for activities other than navigation. Information Technology professionals may use the campus map to identify locations for Wi-Fi hotspots. Universities may indicate to graduating seniors where to line up for commencement. Some campus maps even show real-time occupancy levels of computer rooms in buildings, which starts putting them in the realm of thematic maps. c. Property maps: They can be described with detailed alt-text, put into a MUD text interface, or vectorized into geojson (or something similar) so they can be rendered with Interactive Alt-Text. All the geometries need to be described with landmark, route, and survey information, including distance, direction, shape, size, orientation, and general layout of points, polygons, and lines. All the interactive alt-text method requires is a geojson file of the data to render interactive alt-text with any desired granularity. d. Historical maps: They can be described using detailed alt-text, put into a MUD text interface, or vectorized and turned into geojson (or something similar). Where text is faded or missing, that should be indicated in the description or property of the geometry. If geometries are partial or unclear, then that should be indicated in the description or property of the geometry that is understandable.

Maps can be categorized into thematic or referential, but the one thing they all have in common are geometries. There are thousands of other types of maps than those listed above, including utility, service outage, emergency exit, oceanographic, Steller, fictional, multivariate, time-sequenced, etc. There are also interactive and dynamic maps that change. It’s important to have guidance that encompasses all map types. Having separate rules for each type of map would make the rules too lengthy. All maps convey geometries, so I'm arguing that geometries should be the foundation for any accessible map. All maps need to convey landmark, route, and survey knowledge. There needs to be clear guidance for conveying geometries in alternate text, and that’s what this proposed test provides.

There seems to be two underlying misguided assumptions in the current best practice: (1) alt-text is severely limited in what spatial content it can convey; and (2) Spatial content is inherently visual. The interactive alt-text method presented by maps like this Eclipse map shows it’s possible to convey detailed landmark, route, and survey knowledge. This includes distance, direction, shape, size, orientation, and the general layout of all points, polygons, and lines on a map. This data can be conveyed at the same fidelity as the visual map. It only takes a few minutes to generate this level of detail from a geojson file. Not only is it possible to convey this level of detail, but it’s fast and easy. This method of interactive alt-text is just one way to convey this information, I’m sure there are numerous other ways to convey this level of detail as well. There’s nothing visual about geojson. If a fraction of effort was put into text representation of geometries as is put into the visual representation of geometries, I’m sure there would be a number of easy ways to convey this information. As it stands, we have both the interactive alt-text method above, and the long-form alt-text described in post two.

The blind and low vision community is unhappy with the current alternate text practices for representing maps. Only conveying “summaries”, “critical information”, “author’s intention”, and “Where possible”, is keeping blind people from independently participating in professions requiring the use of digital geographic maps. The “minimum requirements” of the alt text need to be at the level so the alternate text user can use the map for the “equivalent purpose” as their sighted counterparts. This does require a paradigm shift away from only considering alternate text created by hand and static alt-text. On July 7, 2024, the National Federation of the Blind passed a resolution calling for maps to convey the level of detail outlined in this issue. This resolution represents the voice of over 50,000 blind people. Over 50,000 blind people are saying the current method of alt-text on maps is inadequate.

The authors of the WCAG were clear that the alternative text representation needs to show an “equivalent purpose” to the visual representation. This means that blind people should be able to answer any question a sighted person can answer about a map. Using this interactive alt-text eclipse map, or systematic long-form alt-text as described in comment two, blind people can.

Jul 12 '24 13:07 frastlin

I just wanted to add a comment about this statement (from the original post at the top of this thread):

For thematic maps showing more than 3 categories of colors, it’s physically impossible to comply with [SC 1.4.11] as written. Recommended compliance criteria should be as high of contrast as possible color scheme, coupled with patterns to distinguish between the values.

So, I helped write SC 1.4.11, and there is a creative way to solve this contrast problem. I call it the oreo method, or the outline method. Instead of having map items touch each other directly, you can outline each item with one of the following:

outline every thing in white, then you can make all individual items have at least a 3 to 1 contrast with the white outline. If you get stuck with so many colors that you must add data labels and/or patterns to distinguish one item from another...the color still needs to be visible (3 to 1 with the surrounding/background)...but it no longer has to be 3 to 1 color difference with all of the other colors in the scheme...because you've used a data label and/or a pattern to distinguish that thing.

The outline can be white, or black or pick whatever color works best for your color scheme. When things get super complex, you can even go with what I call the "oreo outline"...which is a triple line outline...where the online is a black outline (black cookie) surrounded by a white outline ( white frosting), surrounded by a 2nd black outline (2nd black cookie). With the oreo cookie technique...you can distinguish any item at 3 to 1...because you controlled the background. If black doesn't work as the cookie layer...you could flip it to white cookie, black frosting, white cookie.

Jul 24 '24 22:07 goodwitch

@goodwitch thank you for your suggestion. I updated the test to use either an Oreo border and or patterns if a solid color border is not enough.

I also added a 3rd text interface to post 2. MUD Text interfaces can also be used to show geographic maps.

Jul 30 '24 13:07 frastlin