[go: up one dir, main page]
Menu ▾ ▴

[73c35b]: / anal / gc2gg.m  Maximize  Restore  History

Download this file

31 lines (27 with data), 883 Bytes 

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
% gc2gg: transforms coordinates from geocentric to geographic (lat, lon, h)

% GUISDAP v.1.60 96-05-27 Copyright Asko Huuskonen and Markku Lehtinen

%

% Thanks to J. Murgin (KGI Reprot NO 80:2), EISCAT analysis package, and P.Pollari

%

% See also: gg2gc, loc2gg

%

% function gg=gc2gg(gc)

function gg=gc2gg(gc)



factor=pi/180;        % conversion factor from degrees to radians

% earth radius (km) and flatness factor

r_earth=6378.135;

g=1.00673944;



if gc(1)==0 & gc(2)==0,

  fprintf('Beware of the spinning earth axis!\n');

  gg=[90, 0, gc(3)-r_earth/g];

else

  gg(2)=atan2(gc(2),gc(1))/factor;

  r0=sqrt(sum(gc(1:2).*gc(1:2)));

  xi0=gc(3)/(r0*sqrt(g));

  xi_iter=r_earth*(g-1)/(g*r0);

  tanxi=xi0;

  tanxi=xi0+xi_iter*tanxi/sqrt(1+tanxi^2);

  tanxi=xi0+xi_iter*tanxi/sqrt(1+tanxi^2);

  gg(1)=atan(sqrt(g)*tanxi)/factor;

  gg(3)=sqrt(1+g*tanxi^2)*(r0-r_earth/sqrt(1+tanxi^2));

end;