Grid Convergence

373-21

The definition of grid convergence is ambiguous because textbooks on geodesy, cartography, navigation, and surveying are not consistent on how this angle is calculated. In a world where navigation and surveying have become global activities, this has led to considerable confusion. This confusion may be found in software where grid convergence may be calculated without explicitly stating the convention applied. This guidance note clarifies the various terms and conventions in use.

Document Type: Report

Report Number: 373-21

Document Tags: Geodesy

Published Date: 06 Aug 2013

Last Reviewed: 27 Jun 2025

Latest Version: 1.20