Question

What is datum? Explain how WGS84 is better than any local datum used in GIS.

Hint:

WGS84 enables consistent coordinates for global navigation and mapping.

Answer 1

A datum is a reference system used to model the shape and size of the Earth and to define coordinate systems for mapping and spatial analysis.
It consists of an ellipsoid (mathematical model of Earth’s shape) and its orientation relative to the Earth’s center of mass.
Datums can be local or global.
A local datum, like the Everest Datum used in India, fits a specific region well but may not align accurately worldwide.
WGS84 (World Geodetic System 1984) is a global datum developed for GPS and worldwide mapping.
WGS84 is more accurate because it uses satellite measurements to fit the entire Earth, aligning with its center of mass and providing consistent coordinates globally.
This makes it ideal for GPS navigation, global datasets, and integration across countries.
Unlike local datums that may vary regionally, WGS84 supports seamless sharing and overlaying of geospatial data from different sources worldwide.
Therefore, WGS84’s global consistency makes it more reliable than any local datum in modern GIS applications.