The ability to navigate a path between the stars to a high degree of accuracy is a vital requirement for even the most primitive of interstellar vessels. It is rarely realised by the general public just how difficult such a feat is. Every object in the Milky way galaxy is in a state of motion relative to every other object. Even extra-galactic objects are moving, meaning that there is no universal fixed point of reference for a starship to use as a basis for charting a course.
Starfleet has long striven to fit their ships with the very latest and most advanced sensor and scanner systems. Stellar Cartography uses these systems both for navigational purposes, and for scientific research. For instance, the Stellar Cartography department of a Galaxy class starship includes on the one hand a laboratory which can model planetary formation far in advance1, and on the other a large holographic imaging chamber capable of displaying galactic maps of a high resolution.2
USS Voyager used a combination of Starfleet and Borg technology to expand her Stellar Cartography section to include an astrometrics laboratory. Somewhat similar in fuction to the holographic chamber of the Galaxy class, astrometrics used new-generation sensors to allow detailed information to be obtained across thousands of light years and displayed it on a large viewscreen.3
Whilst lacking the glamour of weapon and shield systems, it seems clear that Stellar Cartography will remain a key component of Federation Starships for the forseeable future.