Contents
Introduction
Like many graphical presentation media, most web mapping solutions are particularly challenged to meet accessibility requirements, especially in the public sector. This guide discusses how to configure your InstantAtlas dynamic report to optimise accessibility.
The HTML5 Technology
The InstantAtlas Desktop templates are used to create dynamic reports that render in a web browser using HTML5.
HTML5 reports can be viewed in any Internet browser compatible with the HTML5 Canvas element. Most modern browsers support HTML5 such as Internet Explorer 9+, Firefox, Chrome, Opera and Safari (version 5.1.4 or later).
A key benefit of HTML5 is that it can render multimedia content without the need to install a plug-in or a player application. HTML5 is able to run on any desktop in addition to mobile devices such as iPhones, Android devices, iPad, tablets and smartphones.
InstantAtlas Features to Address Accessibility
InstantAtlas is a software toolset which properly handled by the publisher, can be largely configured to address the needs of many physically-challenged user communities. Like any graphic presentation, it is incumbent on the web-master to decide what alternative data presentation exists around each InstantAtlas deployment.
Accessible Table
Dynamic reports include XSLT that will translate the XML data file, data.xml, into a readable HTML table if the XML is linked to directly; this is done by replacing the “atlas.html” file in the URL to the report with “data.xml”. A link to this file can be added on the same web page as the dynamic report itself to provide a tabular alternative to the report. The XSLT used to render this XML can be customised if required.
Since HTML5 reports read data from JSON data files (data.js), the XML data file(s) must be added into the HTML5 report folder to enable this functionality. The InstantAtlas Excel and Access Data Managers both allow export of the data to JSON or XML.
CSS Style Sheets / Quality of Text and Graphics
Object line, font size and colour properties can be freely reconfigured from their initial default values using the InstantAtlas Designer and Style Editor. The CSS for a report can also be edited in any text editor. To meet the needs of users with specific sight impairments, the same report can be loaded with different pre-published config.xml and default.css combinations using URL parameters.
Selectable Legend Colour-Swatches
Colour palettes for the representation of map polygons, lines and points as well as lines and bars in each of the charts can be presented to enable the end-user to switch legend preferences. The default colours offered are (blue shades, red/blue contrast and black-grey-white scales). The background colours of the dashboard can also be selected to provide good visual contrast. Many of the palettes offered are based on research for ColorBrewer (Penn State University) with their “colorblind safe” designations.
InstantAtlas reports are designed for use with a mouse when viewed on desktop computers to navigate and click on different parts of the dashboard. The same interaction can be achieved on the keyboard by enabling MouseKeys.
Zooming Capability
The text and graphics in HTML5 reports can be enlarged using the standard zoom feature of web browsers to enable easier use for those with impaired vision.
Addition of Buttons
It is easy to add buttons to an InstantAtlas report. These buttons can be hyperlinked to files for download, or alternative views of the data.
Metatext
The provision of an indicator context-sensitive “metatext” box can be used in reports to provide commentary on the specific data being visualized.
Pop-up Settings
Pop-ups do not need to be enabled to view reports and tool-tips.
JavaScript
InstantAtlas HTML5 reports require scripting to be enabled in the web browser.
Ability to Use Screen Readers
In general screen readers can read the textual parts of an InstantAtlas dynamic report, however different screen readers might produce different results. The most meaningful results are achieved when a screen reader is used on text based components such as the data table, comparison table, metadata box, statistics box and static text elements.
Creating alternative views of the data
From version 6.10.0 onwards, the InstantAtlas Excel Data Manager add-in includes a function that allows the data from a formatted Excel workbook to be exported to a CSV file with simple structure. While a formatted Excel workbook might not be suitable to be used with screen readers (mainly due to merged cells), the CSV format would be much more likely to produce acceptable results. The exported CSV file can also be used as a basis to create an even more accessible format e.g. in Excel.