Where do you see the regularity of the onset of the era of great geographical discoveries?

The growth of population and development of European cities led to the fact that each time they needed more resources. There was an intensive development of international trade, but the Ottoman conquest of the Balkans and Asia Minor made it difficult. Cartography and science developed, which suggested new directions for travel. Firearms appeared, including cannons, which made long travel safer to a certain extent. Also, new types of ships appear – the caravel.