
NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Andrés Ruiz
Date: 2009 Mar 26, 09:22 +0100
In [NavList 7769] all values for a, are in nautical miles.
a: Semi-major axis = equatorial
radius. Is the radius of curvature in a meridian plane at the equator.
Using the formula arc = angle(rad)*
a, we have a = 360*60/(2π) [nm]
But also a = 360*60/(2π) [geodetic miles]
The radius is 21600 sexagesimal arcminutes, and geodetic
minutes.
Average minute of geodetic latitude is:
I have attached the meridional parts table that appears in
the “Tratado de Navegación -
I have compared its values, and conclude that uses the
spherical model of the Earth.
The update from the spherical model to al ellipsoidal one must
be done using a model like WGS84, WGS72, NAD83 or EUROPE1950. If this would have
be done by Bowdith, no error of interpretation or concept will arise.
Andrés Ruiz
Navigational Algorithms
http://www.geocities.com/andresruizgonzalez
--~--~---------~--~----~------------~-------~--~----~
Navigation List archive: www.navlist.net
To post, email NavList@navlist.net
To , email NavList-@navlist.net
-~----------~----~----~----~------~----~------~--~---