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Cornell University

Web Accessibility Reviews

All Guidelines

4

Complex images (graphs, maps, charts) must have a text description of all relevant information.

WGAC 2 criterion 1.1.1 Non-text Content (A)
Category Images
ACT Rules

WCAG 2 criterion

1.1.1 Non-text Content (Level A)

Tools and requirements

  • WAVE Extension + Manual Evaluation

Note

This guideline is targeted at "complex images" Please refer to the image categorization guidance in the Definitions section if you are unsure which category the image you are assessing belongs to.

Examples of images that are relevant for this guideline include

  • Graphs and charts (line, pie, bar, etc.)
  • Maps
  • Diagrams
  • Academic scientific posters

Test procedure

All complex images require a long description. Ensure the long description meets the following requirements.

  • Long descriptions must be available and describe all of the important information contained in the complex image.
    • For a chart or graph, a long description would have details of all of the data points in the graph. A common way of doing so would be to link to an accessible data table with all of the data points.
    • For a map, you want a long description to describe the details the map is trying to provide. For instance, if it is there for directions, a text alternative describing how to navigate to the location should be provided. If the map is designed to highlight a region, then a text alternative should describe how far the region extends with as much detail as necessary.
      • Instructions based on sensory characteristics based on the real world are okay to provide.
    • For a diagram or other complex image (such as a flow chart or scientific poster), the long description must include all the information in the diagram in text format. A flow chart can usually be converted to an unordered list. Other diagrams will need lengthy text descriptions, and these text descriptions should be formatted with headings and semantic markup.
  • The location of the long description must be easy to find. One of the following techniques must be present.
    • The location of the long description is included in the alt text of the complex image.
    • The long description is in text or in a link directly adjacent to the image.
    • The long description is in the same role="group" as the complex image.
    • Note While longdesc is meant for this type of application, it does not have good assistive technology support, and must be supplemented with one of the other solutions.

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