An application is an applied use of a technology. For example, online shopping is an application of Internet technology, automobile navigation is an application of GPS technology, and printing driving-direction maps is an application of GIS technology.

GIS offer powerful new tools for the collection, storage, management and display of map related information whereas simulation models can provide decision-makers with interactive analysis tools for understanding the physical system and judging how management actions might affect that system. The water resource applications of GIS will also need to be multifaceted.

Many of the problems involve interactions between the hydrosphere, atmosphere, lithosphere and biosphere. The solutions must serve competing groups of users with many of the important hydrologic processes having local, regional, national and global dimensions. The management of water resources requires a wide range of spatial data from hydrography and water distribution and collection systems representing the status of water resources to phenomena influencing the quality and movement of water such as terrain, climate, soils and land use.

The number of GIS applications is limited only by our own imagination and the availability of data. For instance, the municipal applications alone are numerous, including: