The argument that Voyager didn't have a Stellar Cartography department seems doubtful to me. Part of the job would require updating existing maps, and it's likely every ship in the fleet has one or two people trained to do so. Astrometrics also uses such maps, and ENT establishes that the NX-01 had an astrometrics section. Harry and Seven designed Voyager's astrometrics room, which likely expanded on an already existing department. Holodecks may have been used for a similar purpose, if we're talking about examining 360 degree starmaps.
Tom Paris (in Threshold) managed to retrieve a wealth of astrometric data which I believe got integrated into the living star maps they developed throughout the series. This makes having a stellar cartography lab even more critical.
Also, would seem being able to chart certain parts of space on a big picture view would be more desirable to running through them headfirst. (case in point, the swarm episode.. Though i suppose janeways not wanting to spend 10 months going AROUND their space had some merit..)