Interactive map accessibility principles
Map accessibility is important to people with the following disabilities:
- Blindness
- Colour-blindness
- Low vision
- Deafness
- Motor impairments
- Cognitive impairments
Online maps are inaccessible to people with vision impairments, so a textual alternative (long description) must always be provided. It is also important to include accessibility features within the map so it is accessible to people with other disabilities, e.g. by making the map non-reliant on JavaScript and keyboard accessible.
Accessibility principles specific to the use of maps include, but are not limited to:
- Providing a long description of the map in text or HTML.
- Providing an ALT attribute for image-based maps.
- Ensure client-side image maps have accurate ALT attributes to indicate areas of a map or important markers
- Making the map keyboard accessible.
- Making an HTML version of any JavaScript features of the map.
- Using only high contrast colours
- Ensure that your map design complies with the 4.5:1 colour contrast ratio.
- Not relying on colour to differentiate important parts of the map.
- Ensure that your maps use:
- borders to separate one area from another
- different types of shading and change of colour to indicate different areas
- label markers with an ASCII character and individual colours for different markers.
- Ensure that your maps use:
- Allowing users to increase the size of the map, legend and any text.
- Often maps do not respond to browser requests to increase size, therefore additional methods may be required to:
- provide a “large” version of the map, where the user has increased the normal text size by 200%; and
- maximise a particular point/area, or add a highlight box that shows the particular point/area in a larger size.
- Often maps do not respond to browser requests to increase size, therefore additional methods may be required to: