[Proj] True North Angle

OvV_HN ovv at hetnet.nl
Mon Jun 23 13:57:23 EDT 2008

The DMA manual TM8358.2 has a formula
The convergence can be calculated from grid coordinates or from geographic 

For wide TM applications one could consult the Finnish JHS 154 publication.
See page 20 of the pdf.

Oscar van Vlijmen

----- Original Message ----- 
From: "Hersman, William" <willy.hersman at conocophillips.com>
To: <proj at lists.maptools.org>
Sent: Monday, June 23, 2008 5:52 PM
Subject: [Proj] True North Angle


Does anyone know the formula to calculate the deviation angle between
true north and Universal Transverse Mercator grid north?  Thanks.

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