Re: [Proj] wrong computation of meridinal distance / pj mlfn.c

Peter Albert peter.albert at gmx.de
Wed Jul 13 02:11:28 EDT 2005


Hi Cliff,


> Geocentric latitude is not the same as geodetic latitude

well, I thought I correctly incorporated those differences: The geodetic
latitude is what goes into proj and what is used within the approximation in
pj_mlfn.c. However, for the "manual" integration of the elliptical integral
[int(sqrt(a-es*(cos(t)^2)) dt)] you do have to use the geocentric latitude
(it is just based on the ellipse being defined as x=a*cos(t), y=b*sin(t)).
So I used an arbitrary geodetic latitude with proj and the corresponding
geocentric latitude for my calculations. 

Regards,

     Peter

-- 
5 GB Mailbox, 50 FreeSMS http://www.gmx.net/de/go/promail
+++ GMX - die erste Adresse für Mail, Message, More +++



More information about the Proj mailing list