The following year he travelled with his father in Italy and they made numerous geodesic observations, as well as visiting Bologna where they repaired the gnomon at the Church of San Petronio which Cassini's father had designed nearly thirty years before. Cassini, like his father, was interested in making both astronomical observations and also interested in accurate surveys.
Ang mga sumusunod na taon siya manlalakbay sa kanyang ama sa Italya at ang kanilang ginawa maraming heodesiko obserbasyon, pati na rin ang pagbisita sa Bologna kung saan sila repaired ang gnomon sa Simbahan ng San Petronio na Cassini's ama ay dinisenyo halos tatlumpung taon bago. Cassini, tulad ng kanyang ama, ay interesado sa paggawa ng parehong astronomya obserbasyon at ding interesado sa tumpak na mga survey.