The astrometrics lab was the stellar cartography facility built aboard the USS Voyager in 2374 by Harry Kim and Seven of Nine, combining Starfleet and Borg sensor technology to plot a faster course home.
The lab is unveiled in Year of Hell. Its large curved display and Borg-enhanced sensors measure the radiative flux of billions of stars at once, making it far more accurate than the ship's earlier systems, and the first course it plots trims years from the journey.
Seven of Nine works there most days, and the room becomes her usual station. It is where she locates the USS Prometheus through an alien relay network in Message in a Bottle and where the crew receive letters from home in Hunters.
The lab later carries the regular link with Starfleet established through the Pathfinder Project, including Barclay's first message in Pathfinder and the conversations with families in Author, Author.