Among the many things you can map is where has been mapped and where hasn't. The first of these offers a dramatic view of the known world versus the unknown world as of 1500. The second is from a 1905 British geography book and shows how well different regions of the near east had been surveyed as of that point in time. The best surveyed regions include the Peloponnese, of archaeological interest, Cyprus, a British colony, and Palestine, a future British colony also of considerable archaeological interest.
The first map is from Sami Ongor's Cografi Kesifler ve Tetkik Seyahatlari Tarihi (Istanbul, 1954 Maarif Basimevi). The Second is from D. G. Hogarth's The Nearer East.