gmaze_pv/subfct/subfct_getdS.m

% DS = subfct_getdS(LAT,LON)
% This function computes the 2D dS surface elements centered
% on LON,LAT
%

function varargout = subfct_getdS(Y,X);

ny = length(Y);
nx = length(X);

if nx == size(X,1)
  X = X';
end
if ny == size(Y,1)
  Y = Y';
end

%%% Compute the DY:
% Assuming Y is independant of ix:
d  = m_lldist([1 1]*X(1),Y);
dy = [d(1)/2  (d(2:length(d))+d(1:length(d)-1))/2 d(length(d))/2];
dy = meshgrid(dy,X)';

%%% Compute the DX:
clear d
for iy = 1 : ny
   d(:,iy) = m_lldist(X,Y([iy iy]));
end
dx = [d(1,:)/2 ;  ( d(2:size(d,1),:) + d(1:size(d,1)-1,:) )./2 ; d(size(d,1),:)/2];
dx = dx';

%% Compute the horizontal DS surface element:
ds = dx.*dy;

switch nargout
 case 1
  varargout(1) = {ds};
 case 2
  varargout(1) = {ds};
  varargout(2) = {dx};
 case 3
  varargout(1) = {ds};
  varargout(2) = {dx};
  varargout(3) = {dy};
end   
1	% DS = subfct_getdS(LAT,LON)
2	% This function computes the 2D dS surface elements centered
3	% on LON,LAT
4	%
5
6	function varargout = subfct_getdS(Y,X);
7
8	ny = length(Y);
9	nx = length(X);
10
11	if nx == size(X,1)
12	X = X';
13	end
14	if ny == size(Y,1)
15	Y = Y';
16	end
17
18	%%% Compute the DY:
19	% Assuming Y is independant of ix:
20	d = m_lldist([1 1]*X(1),Y);
21	dy = [d(1)/2 (d(2:length(d))+d(1:length(d)-1))/2 d(length(d))/2];
22	dy = meshgrid(dy,X)';
23
24	%%% Compute the DX:
25	clear d
26	for iy = 1 : ny
27	d(:,iy) = m_lldist(X,Y([iy iy]));
28	end
29	dx = [d(1,:)/2 ; ( d(2:size(d,1),:) + d(1:size(d,1)-1,:) )./2 ; d(size(d,1),:)/2];
30	dx = dx';
31
32	%% Compute the horizontal DS surface element:
33	ds = dx.*dy;
34
35	switch nargout
36	case 1
37	varargout(1) = {ds};
38	case 2
39	varargout(1) = {ds};
40	varargout(2) = {dx};
41	case 3
42	varargout(1) = {ds};
43	varargout(2) = {dx};
44	varargout(3) = {dy};
45	end