Making Charts accessible to persons with disabilities (03-Nov-2009)

Making Charts accessible to persons with disabilities

Disclosed is a system to annotate graphical charts on the Web to allow keyboard and screen reader access to the data making the information available to users of all abilities. This invention is needed because graphs and charts on Web pages are generally inaccessible to users who rely on assistive technology screen reader software to interact with Web pages. A user who can not see the graphical representation of the data is often at a loss to understand the information. Also, people with vision impairments may have difficulty seeing the data and not be able to easily interpret specific points on the charts. Those with cognitive impairments may have trouble reading the specific data points from a chart.

One solution is to summarize the data and any trends in text that accompanies the chart. Since charts may change often due to additional or changing data points, it can be difficult to keep the summaries up to date. Creating the summary also requires human intervention and thus is not a desirable alternative. Another option is to provide the entire data source in table format so that a user can interact directly with the data rather than the graphical representation of the data. In the case of the web, this tabular representation could be provided via a link to another Web page. This is acceptable for small sets of data but becomes unreasonable when the data set is large.

People with disabilities want to be able to interact with the data on the same chart that is used by all users. This invention proposes a mechanism to allow users to interact with the data on the actual chart.

The following describes an implementation for line charts displayed on the Web but could be extended to other chart types and technologies. Consider a line chart which is made up of sales data for a company which manufacturers widgets. The chart is for 2009 and plots sales on the vertical axis and months of the year across the bottom access. The sales of five different widgets are plotted. The chart has a legend for each widget indicating the color and pattern of the line which corresponds to each widget. A screen reader user would move focus to one of the legends and press enter. This would cause the focus to move into the chart onto the first data point on the line representing the data for that widget. The data for that point might be, "January, $2500". This information would be displayed as a tooltip and spoken by the screen reader. A tooltip is a popup that is associated with an element on the page containing additional information about the element. A tooltip is displayed when the trigger element receives focus or the mouse hovers over it. With focus on a data point in the chart, when the user arrows to the right the focus would move to the next data point and "February, $1900" wou...