matlab_class/sample_processing/example_griddata.m

function []=example_griddata();
%object:    a griddata example within gcmfaces

%%%%%%%%%%%%%%%%%
%load grid:
%%%%%%%%%%%%%%%%%

gcmfaces_global;

if isempty(mygrid);
   grid_load;
end;

if myenv.verbose>0;
    gcmfaces_msg('===============================================');
    gcmfaces_msg(['*** entering example_griddata that will define ' ...
        'a 2x2 gridded variable (an bathymetry field here), and then ' ...
        'use griddata to map it to the chosen grid. '],'');
end;

%%%%%%%%%%%%%%%%%%%%%%%
%get sample data: subsampled mygrid.Depth
if myenv.verbose>0;
    gcmfaces_msg('* define test case : subsampled bathymetry');
end;
original_Depth=mygrid.Depth;
original_Depth(original_Depth==0)=NaN;
lon=mygrid.XC; lat=mygrid.YC;
for ff=1:mygrid.nFaces;
    lon{ff}(1:2:end,:)=NaN;
    lat{ff}(1:2:end,:)=NaN;
    original_Depth{ff}(1:2:end,:)=NaN;
    lon{ff}(:,1:2:end)=NaN;
    lat{ff}(:,1:2:end)=NaN;
    original_Depth{ff}(:,1:2:end)=NaN;
end;
lon=convert2vector(lon);
lat=convert2vector(lat);
vec=convert2vector(original_Depth);

%%%%%%%%%%%%%%%%%%%%%%%
%make sure to accomodate the two longitude conventions:
if myenv.verbose>0;
    gcmfaces_msg('* accomodate both lon. conventions, then convert to data vector');
end;
x=[lon-360;lon;lon+360]; y=[lat;lat;lat]; z=[vec;vec;vec];
jj=find(~isnan(z)); x=x(jj); y=y(jj); z=z(jj);

%%%%%%%%%%%%%%%%%%%%%%%
%do the interpolation:
if myenv.verbose>0;
    gcmfaces_msg('* map/interpolate data using griddata');
end;
griddata_Depth=gcmfaces(5);
for ii=1:mygrid.nFaces;
    xi=mygrid.XC{ii}; yi=mygrid.YC{ii};
    zi = griddata(x',y',z',xi,yi);
    griddata_Depth{ii}=zi;
end;

%msk=mygrid.hFacC(:,:,1); griddata_Depth(find(msk==0))=NaN;

%%%%%%%%%%%%%%%%%%%%%%%
%illustrate the result:

figureL;
subplot(2,1,1); set(gca,'FontSize',14);
[X,Y,FLD]=convert2pcol(mygrid.XC,mygrid.YC,original_Depth);
pcolor(X,Y,FLD); axis([-180 180 -90 90]); shading flat;
title('input to griddata');
subplot(2,1,2); set(gca,'FontSize',14);
[X,Y,FLD]=convert2pcol(mygrid.XC,mygrid.YC,griddata_Depth);
pcolor(X,Y,FLD); axis([-180 180 -90 90]); shading flat;
title('output of griddata');

if myenv.verbose>0;
    gcmfaces_msg('* note of caution : griddata puts values on land. ');
    gcmfaces_msg('*** leaving example_griddata');
    gcmfaces_msg('===============================================');
end;
1	gforget	1.13	function []=example_griddata();
2	gforget	1.8	%object: a griddata example within gcmfaces
3	gforget	1.1
4	gforget	1.14	%%%%%%%%%%%%%%%%%
5			%load grid:
6			%%%%%%%%%%%%%%%%%
7
8	gforget	1.11	gcmfaces_global;
9	gforget	1.14
10	gforget	1.15	if isempty(mygrid);
11			grid_load;
12			end;
13	gforget	1.14
14	gforget	1.11	if myenv.verbose>0;
15			gcmfaces_msg('===============================================');
16			gcmfaces_msg(['*** entering example_griddata that will define ' ...
17	gforget	1.14	'a 2x2 gridded variable (an bathymetry field here), and then ' ...
18	gforget	1.11	'use griddata to map it to the chosen grid. '],'');
19			end;
20
21	gforget	1.1	%%%%%%%%%%%%%%%%%%%%%%%
22	gforget	1.12	%get sample data: subsampled mygrid.Depth
23	gforget	1.11	if myenv.verbose>0;
24	gforget	1.12	gcmfaces_msg('* define test case : subsampled bathymetry');
25	gforget	1.11	end;
26	gforget	1.12	original_Depth=mygrid.Depth;
27			original_Depth(original_Depth==0)=NaN;
28			lon=mygrid.XC; lat=mygrid.YC;
29			for ff=1:mygrid.nFaces;
30			lon{ff}(1:2:end,:)=NaN;
31			lat{ff}(1:2:end,:)=NaN;
32			original_Depth{ff}(1:2:end,:)=NaN;
33			lon{ff}(:,1:2:end)=NaN;
34			lat{ff}(:,1:2:end)=NaN;
35			original_Depth{ff}(:,1:2:end)=NaN;
36			end;
37			lon=convert2vector(lon);
38			lat=convert2vector(lat);
39			vec=convert2vector(original_Depth);
40	gforget	1.1
41			%%%%%%%%%%%%%%%%%%%%%%%
42	gforget	1.11	%make sure to accomodate the two longitude conventions:
43			if myenv.verbose>0;
44			gcmfaces_msg('* accomodate both lon. conventions, then convert to data vector');
45			end;
46	gforget	1.12	x=[lon-360;lon;lon+360]; y=[lat;lat;lat]; z=[vec;vec;vec];
47	gforget	1.1	jj=find(~isnan(z)); x=x(jj); y=y(jj); z=z(jj);
48
49	gforget	1.11	%%%%%%%%%%%%%%%%%%%%%%%
50			%do the interpolation:
51			if myenv.verbose>0;
52			gcmfaces_msg('* map/interpolate data using griddata');
53			end;
54	gforget	1.12	griddata_Depth=gcmfaces(5);
55	gforget	1.8	for ii=1:mygrid.nFaces;
56	gforget	1.12	xi=mygrid.XC{ii}; yi=mygrid.YC{ii};
57			zi = griddata(x',y',z',xi,yi);
58			griddata_Depth{ii}=zi;
59	gforget	1.1	end;
60
61	gforget	1.12	%msk=mygrid.hFacC(:,:,1); griddata_Depth(find(msk==0))=NaN;
62	gforget	1.1
63			%%%%%%%%%%%%%%%%%%%%%%%
64			%illustrate the result:
65
66	gforget	1.12	figureL;
67			subplot(2,1,1); set(gca,'FontSize',14);
68			[X,Y,FLD]=convert2pcol(mygrid.XC,mygrid.YC,original_Depth);
69			pcolor(X,Y,FLD); axis([-180 180 -90 90]); shading flat;
70			title('input to griddata');
71			subplot(2,1,2); set(gca,'FontSize',14);
72			[X,Y,FLD]=convert2pcol(mygrid.XC,mygrid.YC,griddata_Depth);
73			pcolor(X,Y,FLD); axis([-180 180 -90 90]); shading flat;
74			title('output of griddata');
75	gforget	1.1
76	gforget	1.11	if myenv.verbose>0;
77			gcmfaces_msg('* note of caution : griddata puts values on land. ');
78			gcmfaces_msg('*** leaving example_griddata');
79			gcmfaces_msg('===============================================');
80			end;