Apache Reference: mod_imap
mod_imap - URL Selection by Image Map Coordinations
Since Apache 1.0, src/modules/standard/mod_imap.c
Rob McCool, Kevin Hughes, Randy Terbush, James H. Cloos, Jr., Nathan Kurz, Mark Cox (1995)
The task of mod_imap is simply to determine the surrounding area of x,y-coordinates (given in the QUERY_STRING) inside a server-based image map and perform a HTTP redirection to the URL corresponding to this area. Although this task is a very specialized one, do not underestimate the difficulty involved in solving this problem. Because image maps can contain arbitrarily complex polygons, a dedicated module to handle this task is only reasonable.
ImapBase ImapDefault ImapMenu