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.
History of cartography
The history of cartography traces the development of cartography, or mapmaking technology, in human history. Maps have been one of the most important human inventions for millennia. People have created and used maps to help them define, explain, and navigate their way through the world. Earliest archaeological maps include cave paintings to ancient maps of Babylon, Greece, China, and India. They began as two-dimensional drawings, and for some time at least in Europe, the Earth was thought to be flat.
Cartography
Cartography (; from Greek χάρτης "chartēs", "papyrus, sheet of paper, map"; and γράφειν "graphein", "write") is the study and practice of making maps. Combining science, aesthetics, and technique, cartography builds on the premise that reality can be modeled in ways that communicate spatial information effectively.
The fundamental problems of traditional cartography are to:
- Set the map's agenda and select traits of the object to be mapped. This is the concern of map editing