Components of a GIS according to Somerset County, NJ:

A working GIS integrates five key components: hardware, software, data, people, and methods.

1. Hardware
   Hardware is the computer on which a GIS operates. Today, GIS software runs on a wide range of hardware types, from centralized computer servers to desktop computers used in stand-alone or networked configurations.
2. Software
   GIS software provides the functions and tools needed to store, analyze, and display geographic information. Key software components are Tools for the input and manipulation of geographic information A database management system (DBMS) Tools that support geographic query, analysis, and visualization A graphical user interface (GUI) for easy access to tools
3. Data
   Possibly the most important component of a GIS is the data. Geographic data and related tabular data can be collected in-house or purchased from a commercial data provider. A GIS will integrate spatial data with other data resources and can even use a DBMS, used by most organizations to organize and maintain their data, to manage spatial data.
4. People
   GIS technology is of limited value without the people who manage the system and develop plans for applying it to real-world problems. GIS users range from technical specialists who design and maintain the system to those who use it to help them perform their everyday work.
5. Methods
   A successful GIS operates according to a well-designed plan and business rules, which are the models and operating practices unique to each organization.