Why are Geographic Information Systems (GIS) important in today's world? They let geographers map the ocean floor.
They define world regions.
They help determine distance.
They allow users to layer map information from different sources.

They allow users to layer map information from different sources.

Explanation:

Geographic information system is important today because it allows users to layer map information from different sources one on top of another.

A geographic information system gathers, stores, visualize and interprets spatially aware data. The spatial attribute of its data makes it different from every other information systems or statistical tool out there. The system is made up of the hardware, software and the people ware. The hardware is usually the computer, gps devices and so on used to collect and interact with data. The software is the environment where the data is stored and interpreted using some applications on the computer. People ware refers to the human technician that interprets the data.

Geographic information system can overlap multiple map layers to make for more robust interpretation.