I have purchased a large number of original old, paper maps, that were originally published in the USA from the 1800's and early 1900's, which carry US copyright notices of prior to 1923.
1) Is my interpretation of copyright law correct in that these maps are in the public domain?
2) If so, can I scan these maps, print and sell copies of them, as they are of railroad historian interest, without copyright infringement issues?
3) Can I save these scans to a format, such as PDF, and effectively copyright such PDF to prevent others from using it? Does merely changing the format of the map image constitute a valid derivative work for copyright purposes?
Dave (New Hampshire)