gmaze_pv/subfct/subfct_getsurf.m

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%        SUB-FUNCTIONS          %%
%% USED BY: SURFBET2OUTCROPS     %%
%%          INTBET2OUTCROPS      %%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% USE DIRECTLY AT YOUR OWN RISK ! %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Master sub-function:
function varargout = subfct_getsurf(CHP,Y,X,LIMITS)

% Limits:
%disp(strcat('Limits: ',num2str(LIMITS)));
O  = LIMITS(1);
MY = sort( LIMITS(2:3) );
MX = sort( LIMITS(4:5) );

% Compute the surface:
[S Smat dS] = getsurf(Y,X,O,MY,MX,CHP);

% Outputs:
switch nargout
 case 1
  varargout(1) = {S};
 case 2
  varargout(1) = {S};
  varargout(2) = {Smat};
 case 3
  varargout(1) = {S};
  varargout(2) = {Smat};
  varargout(3) = {dS};
end %switch nargout


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% This function computes the surface limited southward by
% MY(1), northward by iso-O (or MY(2) if iso-O reaches it),
% eastward by MX(1), westward by MX(2) 
%
% Updates: 
% 20060616: bug fixed in CHPsouth, CHPnorth nanmean
% 20060615: add a default meridional gradient (negative)
%           test on x,y limits
%
function varargout = getsurf(Y,X,O,MY,MX,CHP)

%% Dim:
ny = length(Y);
nx = length(X);
%disp(num2str([ny nx]));

%% Indices:
iymin = max( find( Y<MY(1) ) ); if isempty(iymin),iymin=1; end;
iymax = min( find( Y>MY(2) ) ); if isempty(iymax),iymax=ny;end;
ixmin = max( find( X<MX(1) ) ); if isempty(ixmin),ixmin=1; end;
ixmax = min( find( X>MX(2) ) ); if isempty(ixmax),ixmax=nx;end;
%disp(num2str([iymin iymax ixmin ixmax]));

%% 1- determine the 2D matrix of surface elements defined by
% the grid:
dS = getdS(Y,X);

%% 2- compute the 2D surface matrix where 1 means dS must be 
% counted and 0 must not:

S = ones(ny,nx); % initialy keep all points

% Exclude northward iso-O limits:
% NB: here the test depends on the meridional gradient of CHP
%     if CHP increase (resp. decreases) with LAT then we must
%     keep lower (resp. higher) values than iso-O limit
% a: determine test type:
N = iymax - iymin + 1; % Number of Y points in the domain
CHPsouth = nanmean(nanmean(squeeze(CHP(iymin:iymin+fix(N/2),ixmin:ixmax)),1),2);
CHPnorth = nanmean(nanmean(squeeze(CHP(iymin+fix(N/2):iymax,ixmin:ixmax)),1),2);
SNgrad = (CHPnorth - CHPsouth)./abs(CHPnorth - CHPsouth);
if isnan(SNgrad), SNgrad=-1; end % Assume negative gradient by default
%disp(strcat('Northward gradient sign is:',num2str(SNgrad)));
switch SNgrad
 case  1, testype = 'le'; % Less than  or equal 
 case -1, testype = 'ge'; % Greater than or equal
end %switch
% b: exclude points
S = double(feval(testype,CHP,O));

% Exclude southward limit:
S(1:iymin,:) = zeros(iymin,nx);

% Exclude northward limit:
S(iymax:ny,:) = zeros((ny-iymax)+1,nx);

% Exclude westward limit:
S(:,1:ixmin) = zeros(ny,ixmin);

% Exclude eastward limit:
S(:,ixmax:nx) = zeros(ny,(nx-ixmax)+1);


%% 3- Then compute the surface by summing dS elements 
%     for non nul S points
Skeep = S.*dS;
Skeep = sum(sum(sum(Skeep)));

%% 4- Outputs:
switch nargout
 case 1
  varargout(1) = {Skeep}; % Surface single value
 case 2
  varargout(1) = {Skeep};
  varargout(2) = {S};     % Logical S matrix with included/excluded points
 case 3
  varargout(1) = {Skeep};
  varargout(2) = {S};
  varargout(3) = {dS};    % Surface elements matrix
end %switch nargout


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% This function computes the 2D dS surface elements.
function ds = getdS(Y,X);

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

%%% 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;

1	gmaze	1.1	%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
2			%% SUB-FUNCTIONS %%
3			%% USED BY: SURFBET2OUTCROPS %%
4			%% INTBET2OUTCROPS %%
5			%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
6			% USE DIRECTLY AT YOUR OWN RISK ! %
7			%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
8
9			%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
10			% Master sub-function:
11			function varargout = subfct_getsurf(CHP,Y,X,LIMITS)
12
13			% Limits:
14			%disp(strcat('Limits: ',num2str(LIMITS)));
15			O = LIMITS(1);
16			MY = sort( LIMITS(2:3) );
17			MX = sort( LIMITS(4:5) );
18
19			% Compute the surface:
20			[S Smat dS] = getsurf(Y,X,O,MY,MX,CHP);
21
22			% Outputs:
23			switch nargout
24			case 1
25			varargout(1) = {S};
26			case 2
27			varargout(1) = {S};
28			varargout(2) = {Smat};
29			case 3
30			varargout(1) = {S};
31			varargout(2) = {Smat};
32			varargout(3) = {dS};
33			end %switch nargout
34
35
36			%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
37			% This function computes the surface limited southward by
38			% MY(1), northward by iso-O (or MY(2) if iso-O reaches it),
39			% eastward by MX(1), westward by MX(2)
40			%
41			% Updates:
42			% 20060616: bug fixed in CHPsouth, CHPnorth nanmean
43			% 20060615: add a default meridional gradient (negative)
44			% test on x,y limits
45			%
46			function varargout = getsurf(Y,X,O,MY,MX,CHP)
47
48			%% Dim:
49			ny = length(Y);
50			nx = length(X);
51			%disp(num2str([ny nx]));
52
53			%% Indices:
54			iymin = max( find( Y<MY(1) ) ); if isempty(iymin),iymin=1; end;
55			iymax = min( find( Y>MY(2) ) ); if isempty(iymax),iymax=ny;end;
56			ixmin = max( find( X<MX(1) ) ); if isempty(ixmin),ixmin=1; end;
57			ixmax = min( find( X>MX(2) ) ); if isempty(ixmax),ixmax=nx;end;
58			%disp(num2str([iymin iymax ixmin ixmax]));
59
60			%% 1- determine the 2D matrix of surface elements defined by
61			% the grid:
62			dS = getdS(Y,X);
63
64			%% 2- compute the 2D surface matrix where 1 means dS must be
65			% counted and 0 must not:
66
67			S = ones(ny,nx); % initialy keep all points
68
69			% Exclude northward iso-O limits:
70			% NB: here the test depends on the meridional gradient of CHP
71			% if CHP increase (resp. decreases) with LAT then we must
72			% keep lower (resp. higher) values than iso-O limit
73			% a: determine test type:
74			N = iymax - iymin + 1; % Number of Y points in the domain
75			CHPsouth = nanmean(nanmean(squeeze(CHP(iymin:iymin+fix(N/2),ixmin:ixmax)),1),2);
76			CHPnorth = nanmean(nanmean(squeeze(CHP(iymin+fix(N/2):iymax,ixmin:ixmax)),1),2);
77			SNgrad = (CHPnorth - CHPsouth)./abs(CHPnorth - CHPsouth);
78			if isnan(SNgrad), SNgrad=-1; end % Assume negative gradient by default
79			%disp(strcat('Northward gradient sign is:',num2str(SNgrad)));
80			switch SNgrad
81			case 1, testype = 'le'; % Less than or equal
82			case -1, testype = 'ge'; % Greater than or equal
83			end %switch
84			% b: exclude points
85			S = double(feval(testype,CHP,O));
86
87			% Exclude southward limit:
88			S(1:iymin,:) = zeros(iymin,nx);
89
90			% Exclude northward limit:
91			S(iymax:ny,:) = zeros((ny-iymax)+1,nx);
92
93			% Exclude westward limit:
94			S(:,1:ixmin) = zeros(ny,ixmin);
95
96			% Exclude eastward limit:
97			S(:,ixmax:nx) = zeros(ny,(nx-ixmax)+1);
98
99
100			%% 3- Then compute the surface by summing dS elements
101			% for non nul S points
102			Skeep = S.*dS;
103			Skeep = sum(sum(sum(Skeep)));
104
105			%% 4- Outputs:
106			switch nargout
107			case 1
108			varargout(1) = {Skeep}; % Surface single value
109			case 2
110			varargout(1) = {Skeep};
111			varargout(2) = {S}; % Logical S matrix with included/excluded points
112			case 3
113			varargout(1) = {Skeep};
114			varargout(2) = {S};
115			varargout(3) = {dS}; % Surface elements matrix
116			end %switch nargout
117
118
119
120			%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
121			% This function computes the 2D dS surface elements.
122			function ds = getdS(Y,X);
123
124			ny = length(Y);
125			nx = length(X);
126
127			%%% Compute the DY:
128			% Assuming Y is independant of ix:
129			d = m_lldist([1 1]*X(1),Y);
130			dy = [d(1)/2 (d(2:length(d))+d(1:length(d)-1))/2 d(length(d))/2];
131			dy = meshgrid(dy,X)';
132
133			%%% Compute the DX:
134			clear d
135			for iy = 1 : ny
136			d(:,iy) = m_lldist(X,Y([iy iy]));
137			end
138			dx = [d(1,:)/2 ; ( d(2:size(d,1),:) + d(1:size(d,1)-1,:) )./2 ; d(size(d,1),:)/2];
139			dx = dx';
140
141			%% Compute the horizontal DS surface element:
142			ds = dx.*dy;
143