How were early geographers limited in gathering geographic information?

Obviously they didn't have satellite imagery, or even aerial photographs. In some places they could climb a hill or a mountain to get an overall view of the area, but that is still subject to some perspective issues. It is very hard to see relationships and shapes of rivers and Coastlines and such from the ground.
The best they could do is make sketches of small areas, and try to piece those sketches together by keeping detailed records of directions and distances. Even that becomes problematic when you don't have an accurate compass. The general practice centuries ago was to tell direction based on the sun's position, and that is only as accurate as your timepiece, since the sun is constantly moving. Without a veryaccurate timepiece, they would be limited by how accurate their compass was, and how accurately they could measure distance.
Also the medium used to record sketches could be a problem. Until a few centuries ago, good quality paper was expensive, and a geographer would need tons of it. They would probably use cheaper paper, but then the quality of the sketches would be worse.
As they tried to make maps of larger areas, they pieced together maps of smaller areas made by different people, and then you get problems of scale, and of quality.