| 1 | %'proj_grid': project fields with unstructured coordinantes on a regular grid
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| 2 | % -------------------------------------------------------------------------
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| 3 | % function [A,rangx,rangy]=proj_grid(vec_X,vec_Y,vec_A,rgx_in,rgy_in,npxy_in)
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| 4 |
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| 5 |
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| 6 | function [A,rangx,rangy]=proj_grid(vec_X,vec_Y,vec_A,rgx_in,rgy_in,npxy_in)
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| 7 | if length(vec_Y)<2
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| 8 | warndlg_uvmat('less than 2 points in proj_grid.m','ERROR');
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| 9 | return;
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| 10 | end
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| 11 | diffy=diff(vec_Y); %difference dy=vec_Y(i+1)-vec_Y(i)
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| 12 | index=find(diffy);% find the indices of vec_Y after wich a change of horizontal line occurs(diffy non zero)
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| 13 | if isempty(index); warndlg_uvmat('points aligned along abscissa in proj_grid.m','ERROR'); return; end;%points aligned% A FAIRE: switch to line plot.
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| 14 | diff2=diff(diffy(index));% diff2 = fluctuations of the detected vertical grid mesh dy
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| 15 | if max(abs(diff2))>0.001*abs(diffy(index(1))) % if max(diff2) is larger than 1/1000 of the first mesh dy
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| 16 | % the data are not regularly spaced and must be interpolated on a regular grid
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| 17 | if exist('rgx_in','var') & ~isempty (rgx_in) & isnumeric(rgx_in) & length(rgx_in)==2% positions imposed from input
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| 18 | rangx=rgx_in; % first and last positions
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| 19 | rangy=rgy_in;
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| 20 | % npxy=npxy_in;
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| 21 | dxy(1)=1/(npxy_in(1)-1);%grid mesh in y
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| 22 | dxy(2)=1/(npxy_in(2)-1);%grid mesh in x
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| 23 | dxy(1)=(rangy(2)-rangy(1))/(npxy_in(1)-1);%grid mesh in y
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| 24 | dxy(2)=(rangx(2)-rangx(1))/(npxy_in(2)-1);%grid mesh in x
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| 25 | else % interpolation grid automatically determined
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| 26 | rangx(1)=min(vec_X);
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| 27 | rangx(2)=max(vec_X);
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| 28 | rangy(2)=min(vec_Y);
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| 29 | rangy(1)=max(vec_Y);
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| 30 | dxymod=sqrt((rangx(2)-rangx(1))*(rangy(1)-rangy(2))/length(vec_X));
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| 31 | dxy=[-dxymod/4 dxymod/4];% increase the resolution 4 times
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| 32 | end
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| 33 | xi=[rangx(1):dxy(2):rangx(2)];
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| 34 | yi=[rangy(1):dxy(1):rangy(2)];
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| 35 | [XI,YI]=meshgrid(xi,yi);% creates the matrix of regular coordinates
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| 36 | A=griddata_uvmat(vec_X,vec_Y,vec_A,xi,yi');
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| 37 | A=reshape(A,length(yi),length(xi));
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| 38 | else
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| 39 | x=vec_X(1:index(1));% the set of abscissa (obtained on the first line)
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| 40 | indexend=index(end);% last vector index of line change
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| 41 | ymax=vec_Y(indexend+1);% y coordinate AFTER line change
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| 42 | ymin=vec_Y(index(1));
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| 43 | %y=[vec_Y(index) ymax]; % the set of y ordinates including the last one
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| 44 | y=vec_Y(index);
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| 45 | y(length(y)+1)=ymax;
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| 46 | nx=length(x); %number of grid points in x
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| 47 | ny=length(y); % number of grid points in y
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| 48 | B=(reshape(vec_A,nx,ny))'; %vec_A reshaped as a rectangular matrix
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| 49 | [X,Y]=meshgrid(x,y);% positions X and Y also reshaped as matrix
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| 50 |
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| 51 | %linear interpolation to improve the image resolution and/or adjust
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| 52 | %to prescribed positions
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| 53 | test_interp=1;
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| 54 | if exist('rgx_in','var') & ~isempty (rgx_in) & isnumeric(rgx_in) & length(rgx_in)==2% positions imposed from input
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| 55 | rangx=rgx_in; % first and last positions
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| 56 | rangy=rgy_in;
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| 57 | npxy=npxy_in;
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| 58 | else
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| 59 | rangx=[vec_X(1) vec_X(nx)];% first and last position found for x
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| 60 | % rangy=[ymin ymax];
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| 61 | rangy=[max(ymax,ymin) min(ymax,ymin)];
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| 62 | if max(nx,ny) <= 64 & isequal(npxy_in,'np>256')
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| 63 | npxy=[8*ny 8*nx];% increase the resolution 8 times
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| 64 | elseif max(nx,ny) <= 128 & isequal(npxy_in,'np>256')
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| 65 | npxy=[4*ny 4*nx];% increase the resolution 4 times
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| 66 | elseif max(nx,ny) <= 256 & isequal(npxy_in,'np>256')
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| 67 | npxy=[2*ny 2*nx];% increase the resolution 2 times
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| 68 | else
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| 69 | npxy=[ny nx];
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| 70 | test_interp=0; % no interpolation done
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| 71 | end
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| 72 | end
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| 73 | if test_interp==1%if we interpolate
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| 74 | xi=[rangx(1):(rangx(2)-rangx(1))/(npxy(2)-1):rangx(2)];
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| 75 | yi=[rangy(1):(rangy(2)-rangy(1))/(npxy(1)-1):rangy(2)];
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| 76 | [XI,YI]=meshgrid(xi,yi);
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| 77 | A = interp2(X,Y,B,XI,YI);
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| 78 | else %no interpolation for a resolution higher than 256
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| 79 | A=B;
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| 80 | XI=X;
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| 81 | YI=Y;
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| 82 | end
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| 83 | end |
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