One of the most startling things I learned in law school is that in international law, it really matters what maps say. If your country publishes officially, or allows to be published privately, maps that show a particular set of borders, other countries can use that printed evidence to support a claim in international law that your country accepts those borders. This is one reason why many maps published in the United States include the statement "Boundary representations not authoritative" if there is any doubt or dispute at all about the proper way to draw the boundary line on the map.

When I first lived in Taiwan (1982), under the former Nationalist Party dictatorship, one way the dictatorship showed up in daily life was world maps with BIZARRE territorial claims for the Republic of China, the official name of the regime that still rules Taiwan. Those maps of course showed both Taiwan and the mainland regions of China proper as one country colored in by one map color on the map, but they also showed no country of Mongolia at all--all of that territory was colored as for China--and a northern border of China that spanned Lake Baikal in Russia. (I even saw a historical world globe in a display in the Chiang Kai-shek Memorial in Taipei showing the entire Korean Peninsula in the same map coloring as China, but that wasn't the usual territorial claim in Taiwan by the 1980s, in the interest of friendly diplomatic relations with South Korea.) I also have English-language dictionaries bought during that stay with whole entries (for example, for "Mongolia") blanked out of the pages. Some countries are quite in earnest about this. Taiwan no longer cares much about such things, but maps of the border region of India are a very sensitive issue in India,

http://www.boundaries.com/India.htm

http://www.globalization-group.com/edge/2011/01/india-ban-of...

and plenty of other countries get into disputes about maps.

http://opinionator.blogs.nytimes.com/2012/02/21/manchurian-t...

AFTER EDIT:

The sources here

https://www.cia.gov/library/publications/the-world-factbook/...

and especially here (LONG)

http://www.law.fsu.edu/journals/transnational/vol13_1/donova...

mention the importance of maps in identifying and resolving international boundary disputes.