The Department of Cartography was an organization inside the Federation government that managed the distribution of information concerning traffic patterns, navigational anomalies, and other unusual phenomena inside Federation space.
In 2375, Luther Sloan posed as "Wendell Greer", an assistant director of the Department of Cartography, in order to attend a joint Federation-Romulan conference about the Dominion War on Romulus. (DS9: "Inter Arma Enim Silent Leges")