What is datum in the context of coordinate system?

A datum is one parameter in a geographic coordinate system (GCS). The datum is the part of the GCS that determines which model (spheroid) is used to represent the earth’s surface and where it is positioned relative to the surface.

What is the difference between a datum and a coordinate system?

A datum is simply a foundation and reference for spatial measurements. A system of coordinates is then used to describe those measurements relative to the datum, and a projection is the visual representation of those measurements on a different surface.

Is a datum a reference point?

In surveying and geodesy, a datum is a set of reference points on the earth’s surface against which position measurements are made, and (often) an associated model of the shape of the earth (reference ellipsoid) to define a geographic coordinate system.

What datum is latitude and longitude?

A geographic coordinate system uses longitude and latitude expressed in decimal degrees. For example, WGS 1984 and NAD 1983 are the most common datums today. Before 1983, NAD27 was the most common datum.

What are the different types of coordinate systems?

Coordinate systems. Data is defined in both horizontal and vertical coordinate systems. Horizontal coordinate systems locate data across the surface of the earth, and vertical coordinate systems locate the relative height or depth of data. Horizontal coordinate systems can be of three types: geographic, projected, and local.

What is the definition of coordinate system?

coordinate system. A system of representing points in a space of given dimensions by coordinates, such as the Cartesian coordinate system or the system of celestial longitude and latitude. The American Heritage® Science Dictionary Copyright © 2011.

What is a horizontal datum?

A horizontal (geometric) datum (or reference frame) forms a basis for computations of horizontal positions on the Earth. It is a collection of specific points on the Earth’s surface that have been accurately identified according to their precise northerly or southerly location (latitude) and easterly or westerly location (longitude).