What does the term 'datums' refer to in GIS?

The term 'datums' in GIS refers to reference points or models used to measure locations on the earth's surface. A datum provides a frame of reference for measuring geographical coordinates, such as latitude and longitude. It helps in translating the complex three-dimensional surface of the earth into a two-dimensional plane, allowing for accurate mapping and positioning.

Datums are critical in positioning systems because they define how the latitude and longitude coordinates relate to physical locations on the earth. Different datums use various mathematical models to represent the earth's shape, which can lead to differences in the positioning of coordinates, especially across large areas.

Understanding datums is essential for professionals in GIS, cartography, and surveying because selecting the appropriate datum is vital for ensuring the accuracy of spatial data. Whether working with global datums like WGS84 or regional datums, this concept is foundational to the integrity and usability of geographic information systems.