This is no more accurate than PassPorter's maps (and we do have maps for every park), though it's a bit more detailed as it wasn't designed to fit inside the pages of a book. It is a different approach, as he's chosen to do as Disney does, and cross-reference attractions, etc. by number and color, rather than place the names right on the map.
It doesn't include the Fantasyland expansion, which ours does, it also doesn't have the locations of companion restrooms, First Aid, ATMs, Guest Relations, Tip Boards, and smoking areas; the parade route, and point-to-point travel times within the park.
Our maps have been a point of pride around here for 14 editions now. My apologies for feeling the need to point that out.
Co-Author, PassPorter's Walt Disney World, PassPorter's Disney Cruise Line, and PassPorter's Disneyland and Southern California Attractions