We started day 2 with Collin Smith (and Bene and Lousia) on the Accessibility in Tableau design. The emphasis on the Universal Design for a wider usability rather than just a beautiful design.
We were aware of colour blindness in choosing Tableau default colour palette and the contrast between them. Font size and additional information about context is mentioned in the Visual Best Practice session. There is always a fine balance about include too much information in the viz which makes it cluttered vs not enough information for users to navigate or understand.
Of course there are more areas that we didn't realise or used before such as caption, screen read, keyboard navigation, different layout effects on tooltip etc. There are a lot difficulties which I never paid attention when designing and using Tableau, hence it is good the session pointed out those points for me.
Due to the limited interactions available, I tried to design my visual with the information encode in the title, so a screen reader application can read out for visually impaired user.
The user either select/type through the (postcode) filter to a single postcode, then get information from the text in the bottom.
Or they could select multiple on the map through set action to filter for the BAN on the top.
For keyboard usage, the tab key is the only way to navigate through the view, so I minimised the selections available to reduce the click time.