@ Istria- GIS maps are very useful tools. They are maps that can incorporate any type of geographically referenced information. GIS maps are often very colorful maps that can display things like population density, crime concentrations, or risk levels for natural disasters. The uses of GIS maps are endless, and they can be used in all types of fields like the natural sciences, statistical analysis, criminal justice, urban planning, etc. You can use GIS maps to show traffic congestion hot spots, or to show how social issues relate to geographical regions.
A certificate in GIS is a great compliment to any degree. Most universities have some type of GIS certification program that is accessible to continuing students or non-degree seeking students just interested in the field. Holding a GIS certificate leads to increased pay for many fields. A professor of mine once told me that a GIS certificate can earn an engineer a 10% premium in pay.