[Proj] True North Angle

[OvV_HN]

The DMA manual TM8358.2 has a formula
http://earth-info.nga.mil/GandG/publications/
The convergence can be calculated from grid coordinates or from geographic 
coordinates.

For wide TM applications one could consult the Finnish JHS 154 publication.
See page 20 of the pdf.
http://www.jhs-suositukset.fi/suomi/jhs154


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


Hello,

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