Components of a Geographical Coordinate System: Basic Components (Especially for GATE-Geospatial 2022)

Glide to success with Doorsteptutor material for NSO-Level-2 : get questions, notes, tests, video lectures and more- for all subjects of NSO-Level-2.

Examrace Books on Mapping, GIS, and Remote Sensing prepares you throughly for a wide range of practical applications.

A geographic coordinate system has the following components:

This Diagram Shows Basic Components of Coordinate System

Basic Components

This Diagram Shows Basic Components
  • Angular units: The unit of measure on the spherical reference system.
  • Spheroid: The reference spheroid for the coordinate transformation.
  • Datum: Defines the relationship of the reference spheroid to the Earthีšs surface.
  • Prime meridian: The longitude origin of the spherical reference system.

About the Components

The angular unit of measure is usually degrees, in which the unit represents one part in 360 of a circle. But it may also be grads, in which the unit represents one part in 400 of a circle.

The prime meridian defines the zero value for longitude. (It is not necessary to define a zero value for latitude, since this is always the equator)

The datum specifies the sphere or spheroid. It does a little bit more than that, but we will talk about the rest in the next module.

A sphere is defined by the length of its radius. A spheroid defined by the length of its semi-major and semi-minor axes or by the length of the semi-major axis and the flattening value. (Flattening, or the oblateness of the spheroid, is the ratio of the semi-major to the semi-minor axis.)

Developed by: