Navigational databanks contain hyperspace charts that ideally contain a listing of significant celestial bodies and safe routes through hyperspace to reach important locations. They're often used in conjunction with the astrogation / navicomputer to keep the ship from colliding with any of these bodies during flight. Hyperspace charts are often proprietary information, and as such not every navigational database is created equal; the Trade Federation and the Galactic Empire keep the two most complete and accurate charts of known hyperspace routes.