These maps use web browsers, not Adobe Acrobat; in particular they use HTML image maps.
In both versions, clicking on a placename gives spoken output of the name.
In the version using frames, clicking on a placename puts an enlarged version of that name in a frame above the map.
In the version without frames, clicking on a placename opens a separate window with the enlarged version of the name. You can resize and position the window to suit your preferences.
Page by David Hawgood, 17 April 2003
For list of clear maps by David Hawgood see www.hawgood.co.uk/b/clear.htm