My hobby is making maps - this is called Cartography
That sounds like a very cool hobby, I bet making maps is difficult. 
It can be!  Cartography combines science, aesthetics, and technique
Sounds amazing and I bet it takes many years of practice 
It did take me awhile to learn about it - I did find it interesting that it's been an integral part of the human history for thousands of years.
I hear that the earliest maps were created in the greek era. 
I've heard that too - there are ancient maps of Babylon, Greece - people have created and used maps to navigate their way through the world.
I bet without a map it would be impossible to navigate anywhere especially on the open sea. 
It would be very difficult!  Maps started out being two-dimensional drawings but can also be three-dimensional shapes as in globes and models
Ive seen many types of maps before but I think that 3d versions are my favorite because they show off the land height and hills, mountains ect.