Hello Maae10-ga, and thanks for an interesting question.
In general, public domain material remains in the public domain, and
there is no way for anyone to somehow take private ownership of public
However, the particular *way* in which you present public domain
material can certainly be protected by copyright.
Let's say you reproduce a Table from a Bureau of Census report (just
to invent an example) in a document of your own. The original table
is still public domain. However, anything you've added in your report
-- a title, new column headings, explanatory notes, original graphics
-- can be protected by copyright.
The result is that, other users of your report would be limited in how
they could use, say, a photcopy of your table, since it includes
original material of your own that is protected by copyright.
However, they would have no restrictions on going to the original
Census report and copying the public domain table that you originally
For another person to "get around" your copyright, they would need to
remove any original material that you provided -- potentially a
difficult prospect, since it would mean closely comparing your report
to the original public domain work in order to identify all the
Similarly, if you downloaded public domain data and presented it in
your own original charts, tables, maps, etc., these materials can be
protected by copyright, but the underlying data remains in the public
domain as is accessible to anyone.
I've assumed here that you are asking relative to copyright law in the
United States, but I believe the situation is the same in many other
countries as well.
The Copyright Office for the U.S. is located at the Library of
Congress. They maintain a very useful website, and I suggest you have
a look at it, particularly their "copyright basics" page at:
The site specifically addresses the question of "Publications
Incorporating U. S. Government Works" and suggests that such works
include the following type of compyright statement:
Example: © 2002 Jane Brown. Copyright claimed in Chapters 7-10,
exclusive of U. S. Government maps
Note that this language is suggested, but is not mandatory.
I hope this is the information you need. But if anything is not
clear, or requires further elaboration, let me know through a Request
for Clarification, and I'll be glad to provide additional information.
No search strategy was used for this question; instead, I relied on
personal knowledge of copyright law and familiarity with the Copyright