They weren't as accurate as they could be, in fact some were just based off of educated guesses.
Some of them were very hard to read and not quite right. Now a days they are a lot better
Ancient maps suffered from several problems, including inaccuracy due to reliance on limited knowledge and reports, symbolic representations that created confusion, inconsistent scales, and the inclusion of mythical locations. These issues made ancient maps less reliable for navigation and understanding of geography. Improvements in exploration and measurement over time eventually led to more accurate maps.
;