2.01.08 Text equivalents: Image-map navigation
Because image map areas may be very small in size it is always a good idea to have a separate set of text links for each image-map link area. Consider London in the image-map below.
The original image has an alt text of "Map of UK and Eire" then each mapped region also has a relevant alt text e.g. "Wales". Each location on the map is duplicated in the text links.
It is very rare for an image-map to require server-side processing instead of client-side. It is highly recommended that they are avoided completely, but, if an absolute necessity, please ensure that a set of text link equivalents are present.