Open map List

Global vertical datum

Introduction

There two different definitions of a global vertical datum:

It is an globally defined ellipsoid used as reference surface for measuring geodetic heights.
It is a Geoid used as reference surface for measuring orthometric heights.

Given the definition of the Geoid, global vertical datums can be defined by gravity satellites. These satellites measure the earth's gravity. The variations in gravity are converted to heights that can be compared globally all over the world (so mountain ranges in America can be measured against those in Europe). The local datum systems can be linked together which simplifies height-related issues.

Synonyms

global height datum

Learning outcomes

7 - Coordinate systems and map projections

Explain the relevance of reference surfaces, coordinate systems, and coordi-nate transformations in mapping (level 1 and 2).

Outgoing relations

Global vertical datum is a kind of Vertical datum
Global vertical datum is modelled by Ellipsoid

Incoming relations

Geoid is a kind of Global vertical datum

Learning paths

1.04 Spatial Referencing: Coordinate Systems and Map Projections