MATLAB: Contour plot of concentration of chemical species

contour plot of concentration of chemical species

Hi. I am releasing a chemical species CHX (N units) in a chamber. The size of the chamber is 100 X 100 X 100 cms^3. I want to plot the contour/surface plot of concentration of this chemical species in the chamber at different spatial locations.
I want to look at the concentration profiles overlapped or plotted on one plane, say X-Y plane (100 X 100 cm^2).
I am using a digital chemical analyzer which gives the X and Y vectors, X and Y which give the spatial location. Each and every (X,Y) corresponds to a spatial location at which the chemical species is present.
For example, if a given (X,Y) shows up "m" times it, means that there are "m" units of that species at that location. In my surface plot, at that particualr (X,Y), I want the value to be m/N (with some colormap). The same is with other (X,Y) locations.
Can someone help me with this?

Best Answer

Try this example: 
xy = randi(9, 100, 2);                                      % Matrix Of ‘x’ and ‘y’ Positions
[Uxy,ia,ic] = unique(xy, 'rows');                           % Unique Rows
tally = accumarray(ic, 1);                                  % Tally Numbers Of Unique Row Repeats
Freq = [Uxy, tally];                                        % Concatenated Matrix
xv = min(xy(:,1)):max(xy(:,1));                             % ‘x’ Vector For Interpolation
yv = min(xy(:,2)):max(xy(:,2));                             % ‘y’ Vector For Interpolation
[X,Y] = ndgrid(xv,yv);                                      % Create Interpolation Grid
Z = griddata(Freq(:,1), Freq(:,2), Freq(:,3), X, Y);        % Interpolated Grid Of ‘tally’ Values
figure
contourf(X, Y, Z)                                           % Contour Plot
colorbar
Experiment to get the result you want.
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