matlab_class/sample_processing/example_interp.m

function []=example_interp();
% EXAMPLE_INTERP illustrates interpolation capabilities
%   by going back and forth between gcmfaces grid and
%   longitude-latitude arrays

gcmfaces_global;

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
if myenv.verbose>0;
    gcmfaces_msg('===============================================');
    gcmfaces_msg(['*** entering example_interp: illustrate ' ...
        'interpolation capabilities to get in and out of gcmfaces'],'');
end;

%%%%%%%%%%%%%%%%%
%load grid and setup test case:
%%%%%%%%%%%%%%%%%

if isempty(mygrid);
   grid_load;
end;

%target locations:
lon=[-179.75:0.5:179.75]; lat=[-89.75:0.5:89.75];
[lat,lon] = meshgrid(lat,lon);

%original field:
m=mygrid.mskC(:,:,1);
fld=m.*mygrid.Depth;

%%%%%%%%%%%%%%%%%%%%%%%
%interpolate mygrid.Depth to lon-lat grid:

if myenv.verbose>0;
    gcmfaces_msg('* interpolate mygrid.Depth to lon-lat grid');
end;

fld_interp=gcmfaces_interp_2d(fld,lon,lat);

if 0;
%use sparse matrix method:
interp=gcmfaces_interp_coeffs(lon(:),lat(:));
%
tmp1=convert2vector(fld,'new');
tmp0=1*~isnan(tmp1);
tmp1(isnan(tmp1))=0;
%
tmp0=interp.SPM*tmp0;
tmp1=interp.SPM*tmp1;
%
fld_SPM=reshape(tmp1./tmp0,size(lon));
end;

%%%%%%%%%%%%%%%%%%%%%%%
%interpolate back to mygrid.XC, mygrid.YC:

if myenv.verbose>0;
    gcmfaces_msg('* interpolate back to gcmfaces grid');
end;

fld_reinterp=gcmfaces_interp_2d(fld_interp,lon,lat,'linear');

%%%%%%%%%%%%%%%%%%%%%%%
%remap to gcmfaces grid using extrapolation:

if myenv.verbose>0;
    gcmfaces_msg('* remap to gcmfaces grid using extrapolation');
end;

fld_remap=gcmfaces_remap_2d(lon,lat,fld_interp,0,m);

%%%%%%%%%%%%%%%%%%%%%%%
%illustrate results:

figureL;
subplot(2,1,1); set(gca,'FontSize',14);
[X,Y,FLD]=convert2pcol(mygrid.XC,mygrid.YC,fld);
pcolor(X,Y,FLD); axis([-180 180 -90 90]); shading flat;
title('original field');
subplot(2,1,2); set(gca,'FontSize',14);
pcolor(lon,lat,fld_interp); axis([-180 180 -90 90]); shading flat;
title('interpolated field');

figureL;
subplot(2,1,1); set(gca,'FontSize',14);
[X,Y,FLD]=convert2pcol(mygrid.XC,mygrid.YC,fld_reinterp);
pcolor(X,Y,FLD); axis([-180 180 -90 90]); shading flat;
title('reinterpolated field');
subplot(2,1,2); set(gca,'FontSize',14);
[X,Y,FLD]=convert2pcol(mygrid.XC,mygrid.YC,fld_remap);
pcolor(X,Y,FLD); axis([-180 180 -90 90]); shading flat;
title('remapped field');


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
if myenv.verbose>0;
    gcmfaces_msg('*** leaving example_interp');
    gcmfaces_msg('===============================================');
end;


1	gforget	1.13	function []=example_interp();
2	gforget	1.16	% EXAMPLE_INTERP illustrates interpolation capabilities
3			% by going back and forth between gcmfaces grid and
4			% longitude-latitude arrays
5
6			gcmfaces_global;
7
8			%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
9			if myenv.verbose>0;
10			gcmfaces_msg('===============================================');
11			gcmfaces_msg(['*** entering example_interp: illustrate ' ...
12			'interpolation capabilities to get in and out of gcmfaces'],'');
13			end;
14	gforget	1.1
15			%%%%%%%%%%%%%%%%%
16	gforget	1.16	%load grid and setup test case:
17	gforget	1.1	%%%%%%%%%%%%%%%%%
18
19	gforget	1.15	if isempty(mygrid);
20			grid_load;
21			end;
22	gforget	1.12
23	gforget	1.16	%target locations:
24			lon=[-179.75:0.5:179.75]; lat=[-89.75:0.5:89.75];
25			[lat,lon] = meshgrid(lat,lon);
26
27			%original field:
28			m=mygrid.mskC(:,:,1);
29			fld=m.*mygrid.Depth;
30	gforget	1.1
31			%%%%%%%%%%%%%%%%%%%%%%%
32	gforget	1.16	%interpolate mygrid.Depth to lon-lat grid:
33
34	gforget	1.12	if myenv.verbose>0;
35	gforget	1.16	gcmfaces_msg('* interpolate mygrid.Depth to lon-lat grid');
36	gforget	1.12	end;
37	gforget	1.16
38			fld_interp=gcmfaces_interp_2d(fld,lon,lat);
39	gforget	1.1
40	gforget	1.19	if 0;
41			%use sparse matrix method:
42			interp=gcmfaces_interp_coeffs(lon(:),lat(:));
43			%
44			tmp1=convert2vector(fld,'new');
45			tmp0=1*~isnan(tmp1);
46			tmp1(isnan(tmp1))=0;
47			%
48			tmp0=interp.SPM*tmp0;
49			tmp1=interp.SPM*tmp1;
50			%
51			fld_SPM=reshape(tmp1./tmp0,size(lon));
52			end;
53
54	gforget	1.1	%%%%%%%%%%%%%%%%%%%%%%%
55	gforget	1.17	%interpolate back to mygrid.XC, mygrid.YC:
56	gforget	1.1
57	gforget	1.16	if myenv.verbose>0;
58	gforget	1.17	gcmfaces_msg('* interpolate back to gcmfaces grid');
59			end;
60
61	gforget	1.18	fld_reinterp=gcmfaces_interp_2d(fld_interp,lon,lat,'linear');
62	gforget	1.17
63			%%%%%%%%%%%%%%%%%%%%%%%
64			%remap to gcmfaces grid using extrapolation:
65
66			if myenv.verbose>0;
67			gcmfaces_msg('* remap to gcmfaces grid using extrapolation');
68	gforget	1.1	end;
69
70	gforget	1.16	fld_remap=gcmfaces_remap_2d(lon,lat,fld_interp,0,m);
71
72	gforget	1.1	%%%%%%%%%%%%%%%%%%%%%%%
73	gforget	1.16	%illustrate results:
74	gforget	1.1
75	gforget	1.12	figureL;
76	gforget	1.17	subplot(2,1,1); set(gca,'FontSize',14);
77	gforget	1.16	[X,Y,FLD]=convert2pcol(mygrid.XC,mygrid.YC,fld);
78			pcolor(X,Y,FLD); axis([-180 180 -90 90]); shading flat;
79			title('original field');
80	gforget	1.17	subplot(2,1,2); set(gca,'FontSize',14);
81	gforget	1.16	pcolor(lon,lat,fld_interp); axis([-180 180 -90 90]); shading flat;
82			title('interpolated field');
83	gforget	1.17
84			figureL;
85			subplot(2,1,1); set(gca,'FontSize',14);
86			[X,Y,FLD]=convert2pcol(mygrid.XC,mygrid.YC,fld_reinterp);
87			pcolor(X,Y,FLD); axis([-180 180 -90 90]); shading flat;
88			title('reinterpolated field');
89			subplot(2,1,2); set(gca,'FontSize',14);
90	gforget	1.16	[X,Y,FLD]=convert2pcol(mygrid.XC,mygrid.YC,fld_remap);
91	gforget	1.12	pcolor(X,Y,FLD); axis([-180 180 -90 90]); shading flat;
92	gforget	1.16	title('remapped field');
93
94
95			%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
96			if myenv.verbose>0;
97			gcmfaces_msg('*** leaving example_interp');
98			gcmfaces_msg('===============================================');
99			end;
100	gforget	1.1
101