Not sure if this will help, but two sources I have used for maps for my books are the US CIA World Factbook and the United Nations Cartographic Department, links shown below. Both allow you to use their maps in your books.
The CIA maps should be used as-is but the CIA logo may not be included see link below for details.
The UN has a different policy which is helpful to book makers. You can use the maps as-is in which case you need to leave the UN information (map number, logo, etc) on the map. But you can also modify the maps (I use pushpins and mark routes). In that case you must remove the UN information, you can see the usage details in this link
Although I have yet to use them, Google Maps can be used (with a number of caveats), details in the link below.
I use Photoshop to edit the maps and then save them as .png rather than .jpg. PNG uses a lossless compression algorythm which provides sharper images when they contain text, fine lines, etc like you'd find on a map. JPEGs often introduce "jaggies" especially when you scale them.