Below is the book and the teachers that would have taught Confederate officers of West Point.

West Point "Manual of Topographical Drawing."

By Lt. R. S. Smith and Professor of Drawing Robert W. Weir,

1859

The back where the figures are located should help.

https://books.google.com/books?id=rg87AAAAMAAJ&pg=PR3&lpg=PR3&dq=%22Robert+W.+Weir%22+topography&source=bl&ots=CiziDUWC4l&sig=VipYie0eAjyflm7psy-pSpFHVMo&hl=en&sa=X&ved=0ahUKEwiYh572qq3MAhUHMyYKHeCsDu0Q6AEIHzAB#v=onepage&q=%22Robert%20W.%20Weir%22%20topography&f=false