Plotting Multiple Shaded Uncertainties

Hi, I am relatively new to coding and having an issue plotting my data. I get files with element concentrations and uncertainties and I'd like to plot many of them on one figure with their corresponding figures shaded. I've gotten this code to work for shading the uncertainty for a single element, but I'm not sure this is accurate and the legend is offset (counting the shading as entries). Ideally I won't need a string of code for each element (I have 11 in my code currently but we measure 140). Thanks for any input!

X = Xactdata.Date(Data); % dates & times from instrument 
Elements = [Xactdata.SULPHUR(Data),Xactdata.CHLORINE(Data),Xactdata.POTASSIUM(Data),Xactdata.CALCIUM(Data),Xactdata.TITANIUM(Data),Xactdata.IRON(Data),Xactdata.COPPER(Data),Xactdata.ZINC(Data),Xactdata.ARSENIC(Data),Xactdata.BROMINE(Data),Xactdata.BARIUM(Data)]; %element concentration
E_err = [Xactdata.S_U(Data),Xactdata.Cl_U(Data),Xactdata.K_U(Data),Xactdata.Ca_U(Data),Xactdata.Ti_U(Data),Xactdata.Fe_U(Data),Xactdata.Cu_U(Data),Xactdata.Zn_U(Data),Xactdata.As_U(Data),Xactdata.Br_U(Data),Xactdata.Ba_U(Data)]; %element uncertainty
E_Labels = {"S","Cl","K","Ca","Ti","Fe","Cu","Zn","As","Br","Ba"};

figure 
for i = 1:11 %number of elements plotted 
    plot(X, Elements(:,i)) 
    hold on 
    patch([x; flip(x)], [Elements(:,i)-E_err(:,i); flip(Elements(:,i)+E_err(:,i))], 'b', 'FaceAlpha',0.25, 'EdgeColor','none') 
end 
legend(E_Labels)
title('Element Concentrations')
ylabel('Concentration (ng/m^3)')
xlabel('Date (UTC)')

Answer 1

[Star Strider]

That appears to be correct, although it would be necessary to provide the data to check for any errors.

You can prevent the patch plots from appearing in the legend by providing only the plot calls to the legend fucntion:

X = Xactdata.Date(Data); % dates & times from instrument

Elements = [Xactdata.SULPHUR(Data),Xactdata.CHLORINE(Data),Xactdata.POTASSIUM(Data),Xactdata.CALCIUM(Data),Xactdata.TITANIUM(Data),Xactdata.IRON(Data),Xactdata.COPPER(Data),Xactdata.ZINC(Data),Xactdata.ARSENIC(Data),Xactdata.BROMINE(Data),Xactdata.BARIUM(Data)]; %element concentration

E_err = [Xactdata.S_U(Data),Xactdata.Cl_U(Data),Xactdata.K_U(Data),Xactdata.Ca_U(Data),Xactdata.Ti_U(Data),Xactdata.Fe_U(Data),Xactdata.Cu_U(Data),Xactdata.Zn_U(Data),Xactdata.As_U(Data),Xactdata.Br_U(Data),Xactdata.Ba_U(Data)]; %element uncertainty

E_Labels = {"S","Cl","K","Ca","Ti","Fe","Cu","Zn","As","Br","Ba"};

figure

for i = 1:11 %number of elements plotted

hp{i} = plot(X, Elements(:,i)) ;

hold on

patch([X; flip(X)], [Elements(:,i)-E_err(:,i); flip(Elements(:,i)+E_err(:,i))], 'b', 'FaceAlpha',0.25, 'EdgeColor','none')

end

legend([hp{:}], E_Labels, 'Location','best)

title('Element Concentrations')

ylabel('Concentration (ng/m^3)')

xlabel('Date (UTC)')

That should work. (I changed the first patch argument from ‘[x; flip(x)]’ to ‘[X; flip(X)]’ since MATLAB is case-sensitive, and the independent variable appears to be ‘X’ rather than ‘x’.)

.

[Olivia Hakan]

This is great, thank you! Is there any way to have the uncertainty vary color with the species? Right now its the same for all of them.

[Star Strider]

Thank you!

There are 11 elements, so one option would be:

X = Xactdata.Date(Data); % dates & times from instrument

Elements = [Xactdata.SULPHUR(Data),Xactdata.CHLORINE(Data),Xactdata.POTASSIUM(Data),Xactdata.CALCIUM(Data),Xactdata.TITANIUM(Data),Xactdata.IRON(Data),Xactdata.COPPER(Data),Xactdata.ZINC(Data),Xactdata.ARSENIC(Data),Xactdata.BROMINE(Data),Xactdata.BARIUM(Data)]; %element concentration

E_err = [Xactdata.S_U(Data),Xactdata.Cl_U(Data),Xactdata.K_U(Data),Xactdata.Ca_U(Data),Xactdata.Ti_U(Data),Xactdata.Fe_U(Data),Xactdata.Cu_U(Data),Xactdata.Zn_U(Data),Xactdata.As_U(Data),Xactdata.Br_U(Data),Xactdata.Ba_U(Data)]; %element uncertainty

E_Labels = {"S","Cl","K","Ca","Ti","Fe","Cu","Zn","As","Br","Ba"};

cm = turbo(numel(E_labels));

figure

for i = 1:11 %number of elements plotted

hp{i} = plot(X, Elements(:,i)) ;

hold on

patch([X; flip(X)], [Elements(:,i)-E_err(:,i); flip(Elements(:,i)+E_err(:,i))], cm(i,:), 'FaceAlpha',0.25, 'EdgeColor','none')

end

legend([hp{:}], E_Labels, 'Location','best)

title('Element Concentrations')

ylabel('Concentration (ng/m^3)')

xlabel('Date (UTC)')

Testing that —

E_Labels = {"S","Cl","K","Ca","Ti","Fe","Cu","Zn","As","Br","Ba"};
cm = turbo(numel(E_Labels));

figure
hold on
for k = 1:numel(E_Labels)
    patch([0 1 1 0]+(k-1), [0 0 1 1], cm(k,:))
    text(0.5+(k-1), 0.5, E_Labels(k), 'Horiz','center', 'Vert','middle', 'Color','w', 'FontWeight','bold')
end
hold off

Choose whatever colormap you want.

.

[Olivia Hakan]

That worked. Thanks again!

[Star Strider]

As always, my pleasure!