The authors included such detail about the source maps and attached them to the document to help the reader better visualize the text. In many situations readers are sometimes very visual and require attached sources to help them picture the scene, situation, area, etc.
Explanation:
You can get the answer above by observering the attached sources. Depending on what you are reading, the author probably talks about something and wants to help you visualize it. If not, try to interpret the article in a different way or format.
If you still need help, try to post another question on what your confused on ! Hope this helped!
