Highcharts for Accessibility


Highcharts & Elsevier

Since our company’s inception, our mission has been simple: Make it easy for everyone to visualize and consume data on the web, including people with disabilities.

Highcharts offers an accessible interactive chart solution to empower people with disabilities. Each Highcharts license includes our Accessibility module and a flexible sonification API. The Accessibility module allows you to create charts as accessible as possible, whereas the sonification API helps you support multiple ways to bring data to life with sound.

In addition, we are especially committed to delivering tools for creating accessible content, and we routinely collaborate with other companies and institutions in order to advance the state of data visualization accessibility.

In 2015, our initial eight-month collaboration with Elsevier, a global information and analytics company specializing in scientific, technical, and medical content, resulted in an improved system of descriptive tags for charts and graphs.

Prior to the project, many of the industry-standard techniques and solutions for presenting accessible data visualizations involved creating secondary experiences, such as hidden data tables accessible to screen readers.

The challenge with such solutions is that they fail to communicate the nuances of the data (the reason for creating a visualization in the first place.) Therefore, the main goal of our collaboration with Elsevier was to create one experience for all users.

Instead of creating a second “visualization” through shadow DOMs or live regions, we assigned roles and labels to the individual chart elements. When a screen reader interprets the chart, the information is presented in the context of the visualization, not as an external spreadsheet.

Furthermore, by assigning roles and labels to individual elements, our solution creates a structure for the data that enables users to experience the visualization as a whole rather than as an incoherent group of replicated parts.

The project sparked discussions among experts and thought leaders in accessible technologies, including colleagues at IBM who serve on the W3C SVG accessibility task force, and feedback from our users was overwhelmingly positive.

Our collaboration with Elsevier continues as we work on expanding Highcharts’ accessibility features to more complex visualizations, like sparkline charts where understanding the group “at a glance” is essential to grasping the data as a whole. We are also working on bringing the same feature set to Maps.

Highcharts & Georgia Tech

One of the biggest challenges in making visualizations even more accessible for the visually and cognitively impaired is how to communicate trends in data, e.g. a line chart with many peaks and valleys. A screen reader reciting a static data table makes analyzing complex data cumbersome, if not impossible, and undermines the purpose of the visualization. So, how do you enable an impaired user to experience the visualization as intended? One solution to this problem is sonification.

Sonification is a collective term for conveying information or perceptualizing data using non-speech audio. In data visualization, sonification uses tones and alerts to convey visual trends. For example, a chart in a monitoring dashboard might chime if a value reaches a certain threshold.

Sonification is also an effective tool for exploring data, especially large data sets. It can provide visually impaired users with a quick way to scan for trends and patterns in the data, much like sighted users.

To investigate how sonification may be incorporated into complex data visualizations, we are currently collaborating with the Sonification Lab at Georgia Institute of Technology to develop a sonification graphing tool and improve the sonification features of Highcharts. The sonification tool is a web-based application that allows non-technical users to experiment with visualizing data with sound.

The application combines sonification design elements from GIT’s Sonification Sandbox with Highcharts’ visualization library. A user can import data and easily configure sonification settings (instrument, pitch, volume, etc.) The sonification components will then render with the traditional visual elements in one user experience.

Our collaboration with Georgia Institute of Technology gave us access to their decade of sonification research, which we are incorporating into our own sonification editor into our products. As over 80% of Fortune 100 companies use Highcharts, our goal with this project is to elevate the level of global chart accessibility globally.