Corda® Technologies recognizes the importance of providing equal access to information for users who are visually impaired, and is the first and only company to provide multiple data visualization solutions that create accessible, 508-compliant graphs and maps with descriptive text.
There are an estimated 800,000 visually impaired persons currently using the Web. It is estimated that there are 6.5 million Americans age 55 or older that experience severe vision loss; by 2030 this number is projected to double.
The descriptive text is available for a screen reader device to audibly describe a graph or map so a visually impaired user can understand the graphical information. Corda Technologies has included the descriptive text feature in all members of its Corda Server™ family of data visualization solutions to facilitate inclusion of 508-compliant graphs and maps in all Web content.
Corda Server™ graph or map output is interactive for all users, including the visually impaired. Interactive graphs and maps enable all users to drill down to more in-depth information. Sighted users receive additional information by drilling down to another graph, map, or Web page. Non-sighted users access the same additional information by going from one chart with descriptive text to another chart with descriptive text. As the data changes, the graph or map and the descriptive text automatically change to match the new data. This fulfills the requirements of Section 508 of the Rehabilitation Act, which requires that all graphs and maps must be simultaneously offered in a text format that can easily be interpreted by a screen-reader such as JAWS and IBM* Home Page Reader.
Although this law applies only to federal organizations, many private organizations are also realizing the need to provide a method for visually impaired users to access important data.
This section includes the following topics:
When you enable descriptive text, a link appears either next to the bottom-right corner of the Corda image or below it. By default, this link is a blue underlined letter d (d). Clicking it takes the user to a Web page containing a textual description of the chart.
As a screen reader reads over this link, it indicates to the user that descriptive text is available for the image. The user then has the option of having the screen reader read the description of the Corda image.
For example, in the image above, clicking the d link opens a page similar to the following:
This data is fully interactive. What would appear as hover text in a graphical Corda image appears as text right beside the description for each item. Likewise, drilldown links appear next to each item that is enabled for drilldown effects. Visually impaired users are able to drill down from this descriptive text to another Corda image with d-link descriptive text.
Note: Currently, drilldown to custom Javascript* functions or named destinations within the original Web page is not supported in the Corda Builder™ descriptive text output. You may be able to circumvent the Javascript limitation, however, by customizing the descriptive text template so that it includes a predefined Javascript library of the functions you need to access.
When publishing a static graph or map with Corda Builder, select Create d-link descriptive text when you publish the Corda image. For more information on publishing Corda Images, see Publishing the Project.
When publishing an Image Template file for use with dynamic data from Corda Server, enable descriptive text in the code used to embed the Image Template file in the Web application. For more information, see Image Deployment Issues in the Corda 7 Developer Reference.
Configure descriptive settings in the DLink Settings property. More information on this property is available in the Corda 7 Object Reference.
Corda Builder lets you manage the specifics of descriptive text output in the following ways:
When Corda Builder (or Corda Server) generates descriptive text, it uses the contents of the Title textbox as the title at the top of the descriptive text page. Modifying the Title textbox in a Corda image changes the descriptive text title.
Note: If a Title box is defined for a Corda image, it is always displayed as part of the descriptive text.
For more information on the Titles and Textboxes, see Text Boxes.
The Description Type attribute in the DLink Settings property lets you configure descriptive text for either automatic or manual generation.
Automatic: Uses the descriptive text template to automatically generate descriptive text content. Use the Overrides attribute to add or remove specific Corda image content from descriptive text. For more information, see Descriptive Text Overrides, below.
Manual: Disables automatic descriptive text generation and relies solely on the content you specify in the Description attribute and the contents of the Title box, if one is defined.
Corda Builder gives you complete control over the objects in a descriptive text-enabled project, as well as how those objects are described. A descriptive text template file defines the object settings for a project, but Object Properties let you override the template settings on a object-by-object basis.
To override descriptive text template settings
In Object Properties, open the DLink Settings property.
Click the ellipsis button 
in the Overrides
property to open the Descriptive Text
Overrides dialog.
Check the boxes next to the d-link tags you want to override.
Click the Preview
button 
to preview the descriptive text changes.
When finished, click OK.
From the standpoint of a novice user, modifying the descriptive text template might be the most difficult method of changing the descriptive text format because of the high learning curve involved with understanding how the template works. For advanced users, however, this is a powerful and convenient way to control descriptive text. For more information, see Descriptive Text Settings in the Corda 7 Developer Reference.