On a website there is a page which gives details about building including hire data, contact info and other things that can be marked up semantically and accessibly.
On the same page there is a large image which presents a detailed floor plan of the building, including measurements, facilities and a key to denote the various uses of the rooms.
Normally an image that conveys extra meaning to the user can be made more accessible by the inclusion of an alt tag that which would be used to convey that meaning using basic text that could be understood by screen readers etc. however, in the case of a floorplan the data is far too complex to be conveyed like this.
What would be the best way to convey the meaning in a floorplan to a user who was not able to consume visual content?