Early navigators could use Polaris to determine their latitude and their compass to proceed East or West, providing they were in the Northern Hemisphere. What the compass didn't tell the navigators was just how far East or West they were, in other words, what was their longitude. Such information could be critical to a sailor approaching the coast of California on their Easterly journey from China. You needed a sextant sighting from other stars, a very accurate clock, and an ephemeris to obtain your longitude. The first global sailors didn't have an accurate clock or ephemeris so just engaged in the procedure of 'running their Easting or Westing down'. In other words the sailor would put the ship on the known latitude of their intended destination and proceed straight East or West until they found land. When they were approaching the coast many indications were seen. Clouds or land birds were some good indicators. Some would even keep several land birds in a cage and release one if they thought they were near land. A released land bird would fly up and circle the ship until it saw land and then proceed off in a straight line toward it. Of course the 'birds eye view' was a bit farther at altitude because of the curvature of the earth and the sailors knew it and took advantage of that fact. Today we don't need to do any of those things, but I have often seen shore birds on the container ship flying around and getting scraps of stuff laying around on the deck. After we left the dock some would depart and fly off towards the shore. Others would stick around too long and be trapped. Usually they would die do to lack of fresh water. Even today, modern sailors, and probably birds, believe in a global earth.