By default, the file name for each DITA map file is the base name of the file from which the map was generated, with extension .ditamap. This is true for both book files and chapter files.
To specify a different base name for a chapter map file, include the following setting in a chapter configuration file filename.ini named for the DITA file (see §42.1.1 Providing configuration files for individual ditamaps):
[DITAOptions]
; MapName = name to use (without extension) for the chapter ditamap.
MapName = othername
Alternatively, you can insert a DITAMapName PI marker in the DITA file. The content of the DITAMapName PI marker becomes the base name for the map file, overriding any value specified for MapName.
To specify a different base name for a book map file, in your project configuration file:
[DITAOptions]
; BookMapName = name to use (without extension) for the book ditamap.
BookMapName = bookname
You cannot use a PI marker to override the base name for a book map file.