The above map is a combination of original population data (in black and white) and population density changes (represented by the color map)

As a horizontal technology, GIS can help in marketing, operations research, finance, human resources, planning, health care, banking, land management, earth sciences, just to name a few possibilities.

Geographic Information Systems' power comes from its ability to relate information from different sources by using a common attribute: location or, in a broader sense, geography. It has become a truism that most data contains 80% geographic information in explicit form such as a city name or implicitly like a ZIP code, area code or subdivision. 

By organizing apparently unrelated data from diverse files, databases, remotely sensed data around geographic coordinates, a GIS system can analyze, summarize, visualize and derive new information which can show phenomena such as patterns or concentrations that would be difficult to see in traditional tabular report formats.