Is a data download a viable text-alternative to a visual chart?

Question

I have a dashboard with various different at-a-glance charts. For some of them (such as pie charts) it's simple to offer a toggle / alternative view to change from chart to table view, but for more complex charts such as line-charts with multiple datasets and datapoints we'd need to provide a large multi-row / multi-column table to provide that same data.

While we could drastically alter the dashboard layout for full table versions it's not really ideal for at-a-glance feedback. We'd have to move everything around or add horizontally scrolling tables... neither of these are great options.

One suggestion is to add a 'Download Data As CSV' option for each of the charts, which we'll probably be offering anyway. But from a pure accessibility perspective is 'download as data' a valid interpretation of 'Provide a text alternative to visual information' or do we need to provide a text alternative in-app directly?

(WCAG 2.2 reference: https://www.w3.org/WAI/WCAG22/Understanding/non-text-content.html)

Answer 1

Based on what is said in WCAG's Understanding the non-text content and in sufficient techniques related to that, I'd say yes, downloading is an option but with a caveat. This is because one of the sufficient techniques talk about navigating to the textual description (and back from it). Downloading the textual alternative would make that harder for the user.

In Understanding Non-text content's Sufficient techniques, "Situation B: If a short description can not serve the same purpose and present the same information as the non-text content (e.g., a chart or diagram)" there are long text alternative techniques for the Situation B that fit your situation.

• G73: Providing a long description in another location with a link to it that is immediately adjacent to the non-text content
• G92: Providing long description for non-text content that serves the same purpose and presents the same information.

Out of these two G92 is more forgiving as it doesn't talk about navigating back to the original content, in your case the dashboard.

G92 talks about just providing the text alternative:

The objective of this technique is to provide a long text alternative that serves the same purpose and presents the same information as the original non-text content when a short text alternative is not sufficient.

G73 then talks about linking the description to original content:

The objective of this technique is to provide a way to link to remote long descriptions in technologies that do not have a long description feature built directly into them (e.g., longdesc) or where the feature is known to not be supported.

Both use charts as examples, so they are presentative of your situation.

I'd still suggest the linking the description if that is a possibility in your app. That way users don't need to leave your app to read the text alternatives of the charts.