title_body: Using eReader to display maps
upvoted_answer: Since I find scrolling and zooming on an ebook cumbersome, what I would do with a large image/map is divide it in smaller pieces, slightly smaller than my screen resolution (30 or so pixel less -> 15 on each side). After that generate separate HTML pages, for each image part, and put in hyper-links from page to page on the sides (alternatively I would investigate if I could make the image selectable using image maps).
  
  If the map was divided in 9 pieces:
  
  1 2 3 
  4 5 6
  7 8 9
  
  
  Displaying number 5 would look like:
  
       2
   +-------+
   |       |
   |       |
   |       |
  4|       |6
   |       |
   |       |
   |       |
   +-------+
       8
  
  
  Selecting the numbers would get you to that piece of the map. You could extend this with numbers near the corners to go the diagonally linked image pieces.
  
  As with maps printed in books (with numbers to the top and bottom of a page with the page numbers connecting map pieces), you could have a range of pixels overlap between the map-parts.
  
  If you have many pieces, or this is not a one off, you should probably write a program that takes care of the division of the image, the HTML generation and combining in an EPUB.