plotting a 2D line plot using data with 3 variables

Hi,

Could anyone tell me how to best go about plotting a line graph when the y axis data has 3 variables (100x14x24000 [depth x sediment diameter x concentration]) I need to be able to adjust the first 2 variables as will be plotting under different conditions.

any help would be greatly appreciated.

Answer 1

[Voss]

Is something like this what you want to do?

% 100 depth values:
depth = 100:199;
% 14 sediment diameter values:
diameter = linspace(1,2,14);

% some data 100x140x24000
data = depth.'+10*diameter+cosd(permute(1:24000,[3 1 2])/10);
% normalized to [0,1] (like concentrations)
data = (data-min(data(:)))/(max(data(:))-min(data(:)));

% pick a few values to plot
depth_idx_to_plot = [1 50 100];
diameter_idx_to_plot = [1 4 7 10 13];

% plot the lines
figure();
hold on
Ndepth = numel(depth_idx_to_plot);
Ndiameter = numel(diameter_idx_to_plot);
names = cell(1,Ndepth*Ndiameter);
for i = 1:Ndepth
    for j = 1:Ndiameter
        plot(squeeze(data(depth_idx_to_plot(i),diameter_idx_to_plot(j),:)));
        names{Ndiameter*(i-1)+j} = sprintf('Conc @ (Z=%g,D=%.2f)',depth(depth_idx_to_plot(i)),diameter(diameter_idx_to_plot(j)));
    end
end
legend(names,'Location','EastOutside')

[Michael Cooper]

Hi Benjamin,

Thank you for your answer, and apologies but i am still getting to grips with matlab.

What i am trying to do is set the input for the second element.

when i apply a squeeze I have been able to remove one of variables and plot it like this with a rows of depths being selected independantly

1. plot(t,SGSdata_2m.Cg(1,:),'k','DisplayName','2m_Cg','linewidth',2) %5m
2. plot(t,SGSdata_2m.Cg(32,:),'k','DisplayName','2m_Cg','linewidth',2) %4.2m
3. plot(t,SGSdata_2m.Cg(42,:),'k','DisplayName','2m_Cg','linewidth',2) %3.5m

but what i want to be able to do is same as above, but also include the middle variable something like (1,: 8,:)

[Voss]

So SGSdata_2m.Cg is the output from squeeze(), right? Is it size 100x24000? And it has been generated by selecting one value for sediment diameter, is that correct? Something like this:

d_idx = 14;
SGSdata_2m.Cg = squeeze(original_full_data_set(:,d_idx,:));

Is that basically what you mean? If so, then to plot some values for some other sediment diameter, you'd have to go back to the un-squeeze()'d data. For example, to plot the data at the 1st depth and 8th sediment diameter, you could say:

plot(t,squeeze(original_full_data_set(1,8,:)),'k','DisplayName','2m_Cg','linewidth',2)

If that's not what you have in mind, please explain further, and consider posting (a subset of) your data and more of your code.