Long text alternative: why describe a graph?

Hi Rachel

Just working my way through the basic writing for the web - alt text for images.

I quite strongly disagree with your contending that the alt text / or long description should contain a description of the graph or diagram etc.

The reason for using a graph or diagram is because it supposedly demonstrates something that is more difficult to  express in words.

To then turn round and describe this in words is circular, non productive and certainly not helpful - the correct answer to the 9th question in your test basically leaves the user knowing what they can't see but none the wiser.

Telling someone that it's a graph with lines and colours and axes does not help them at all in most cases, in my opinion the space would be much better used explaining the key information that the graph is trying to convey.

It makes sense to say a image is 'two hippos grazing by a river', that is the purpose is the image, to portray that information, but the information portrayed by a graph is not 'red and blue bars showing the relationship between ...', the graph is the messenger, not the message and becomes irrelevant as soon as it is not involved in the delivery.

My opinion, but enjoying the course.


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Hi Bill

Thanks for your input. It's great to get your feedback especially when you feel so strongly.

I know many people write long descriptions of the important content graphs without mentioning the appearance, and the essential information gets through.

But long descriptions are not written for people who can see the graph and get the information the easy way.  Identifying the type of chart is not a deal breaker, but gives the target reader a taste of the experience of a sighted reader using a normal browser. 

One of our main aims at Contented is to enable content authors to fulfil the requirements of WCAG 2.0 (Web Content Accessibility Guidelines 2.0).

WCAG 2.0's Success Criterion 1.1.1 is a very general statement:

"All non-text content that is presented to the user has a text alternative that serves the equivalent purpose... "

"Serves the equivalent purpose" is different from "presents the same information". A graph, for example, is a visual experience allowing a viewer to "see" relationships, patterns and changes over time in data—it does more than just transmit the deductions one can make after studying the graph.

The WCAG 2.0 guidelines are flexible, and there are numerous ways to meet the requirements. In a one-hour course, we can't cover all possibilities. Instead we offer a simple, clear-cut formula, which is easier for people to assimilate in the time. 

More details: Understanding WCAG 2.0

Glad you're enjoying the course otherwise!

Kind regards






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Jul 30, 2010 • Posted by   Weekly links roundup by Communications from DMN

[…] you shouldn’t write long descriptions to describe graphs (or any […]

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