This depends on the type of map. Cartography is the study of maps and charts. A person who studies topographical maps is called topographer.
The field of study that produces maps and charts of the Earth is called cartography.
I agree with the above comments. But if you want to get really fancy, you could go with Selenographer (a person who charts the surface of the Moon) or Selenologer (a person who studies the Moon).
A pedigree chart is a documented record of one's ancestry. Genealogists use pedigree charts to study family lines. Learn more at 23andme.com.
geography
Oceanographer
A person who studies bats is called a chiropterologist.
Oceanographer
scientist
A person who is involved in the astronomical study of sun is called a Heliologist
A person who studies the Earth is called a geologist. Geologists study the composition, structure, and processes of the Earth to understand its history and dynamics.
Is called a Onclolgist. It's a person who are the ones who study cancer and how to treat it.
They are called an astronomer.