A question that arises freqently when talking to first time writers is, what if I want to use material published somewhere else? Can I include it in my book? What do I have to do for it to be legal?
The legal principle used to answer the question is called “Fair Use” which has been developed to determine how copyrighted material may be used by other authors. It weighs the original author’s ownership of her material and right to be compensated for it if someone else wants to publish any part of it against the need of another author to use some of the material in his work.
The U.S. Copyright office lists four elements used to determine whether a use is fair:
- The purpose and character of the use, including whether such use is of commercial nature or is for nonprofit educational purposes
- The nature of the copyrighted work
- The amount and substantiality of the portion used in relation to the copyrighted work as a whole
- The effect of the use upon the potential market for, or value of, the copyrighted work
The 1961 Copyright Law explained the fair use principle in this way: “quotation of excerpts in a review or criticism for purposes of illustration or comment; quotation of short passages in a scholarly or technical work, for illustration or clarification of the author’s observations; use in a parody of some of the content of the work parodied; summary of an address or article, with brief quotations, in a news report; reproduction by a library of a portion of a work to replace part of a damaged copy; reproduction by a teacher or student of a small part of a work to illustrate a lesson; reproduction of a work in legislative or judicial proceedings or reports; incidental and fortuitous reproduction, in a newsreel or broadcast, of a work located in the scene of an event being reported.”
Any material used under the fair use principle must cite the source from which it is take.
If you are uncertain of how the fair use principle applies to the material you want to use, the Copyright Office advises, “The safest course is always to get permission from the copyright owner before using copyrighted material.”
Pat, the U.S. Copyright Office offers some information on the length of copyright on its website. That's probably a good place to start. Part of the question is the original publication date. Another is whether someone who obtained and changed it before publishing a new version and possibly establishing a new copyright. What does the publication in which it appears say? If you found the maps in a library or archive ask the archivist about rights to the material. Doing some research about rights before publishing anything is always a good idea.