GIS can be explained as a computer mapping system which combines a database linked to mapped features. All physical features do have locations and the database linked to the physical location can be used to answer questions about relationships between various physical items. For example a question asked such as "how far is the fire station from my house?" can be answered based on spatial characteristics.
So how can you use GIS? Anything using time and space to ask questions and retrieve answers can be the domain of a GIS. From finding School District Boundaries to knowing City's subdivisions are all possible.
GIS also provides public access to map information via
online interactive maps and PDF maps.
For more information on GIS visit WHAT IS GIS?