Which two types of coordinate systems are predominantly utilized in GIS?

The predominant types of coordinate systems used in Geographic Information Systems (GIS) are geographic and projected coordinate systems. Geographic coordinate systems are based on a three-dimensional spherical model of the Earth and use a set of numbers to define the location of points in degrees of latitude and longitude. This system is essential for locating places on the Earth's surface and is often used in global positioning systems (GPS).

Projected coordinate systems, on the other hand, convert the three-dimensional Earth into a two-dimensional map, which allows for easier measurement of distances, areas, and angles on flat surfaces. These systems employ various mathematical formulas to project geographic coordinates onto a plane, facilitating tasks such as urban planning, resource management, and environmental analysis.

Together, both geographic and projected coordinate systems are vital for ensuring accurate spatial analysis and representation of geographic data. This capability is fundamental to GIS applications, thus making this combination the key choice in the context of the question.