In hydro, GIS has two meanings:
- In the field of geomatics, it stands for Geographical Information System. In the simplest sense, this is software that can assemble and analyse spacial data, such as land ownership data, soil classifications, population distribution, etc.. The analytical tools can be used to extract data from topography (such as the area-elevation curves of a reservoir) and examine the natural land slopes around a reservoir to identify which areas need to be evaluated for slope stability.
- In the field of high voltage electrical engineering, GIS stands for Gas Insulated Switchgear. These are components of the high voltage electrical system that contain a pressurized insulating gas (such as sulphur hexafluoride, SF6). In air, high voltage components need to be separated by several metres to prevent arcing, so outdoor switchyards need to be large. Insulating gas in a GIS switchyard allows the size of the components to be considerably reduced, making it more economical to house the switchgear indoors.