How to add different size arrays to existing graph

I cant get the AM_O, AM_15D, and AM_15G in part 3 of my code to plot onto the existing SolarIrradiance.fig that i made earlier, this is the code that i have so far, the am's are 2002x1 and lambda is a 1x300

close
clear
clc

[Inserted break so folks can copy/paste w/o wiping out their existing environment...dpb]

r_d = 1.50e11; % distance from Earth to Sun
r_s = (1.39e9)/2; % radius of the sun 
fw =(r_s/r_d)^2;
t_s = 5800; % temp in kelvin
h = 6.626e-34; % in J*s
k_b = 1.381e-23; % in J/K
c = 2.998e8; % in m/s
syms lambda L_sun
lambda = (0.001:0.01:3)*1e-6;
L_sun = fw .* (2*pi*h*c.^2) ./ lambda.^5 .*...
    1./(exp((h*c)./(lambda*k_b*t_s)) -1);
figure(1)
plot(lambda, L_sun, 'b-', 'LineWidth', 2);
xlim([0 3e-6]);
xlabel('Wavelength (um)');
ylabel('Spectral Irradiance (W*m^2/m^-1)');
legend('L_s_u_n')
set(gcf, 'PaperPositionMode', 'manual');
set(gcf, 'PaperUnits', 'inches');
set(gcf, 'PaperPosition', [0 0 6.75 5]);
print('SolarIrradiance.tif', '-dpng', '-r600')
saveas(gcf, 'SolarIrradiance.fig')

%%
% Part 2.
maxL_sun = max(L_sun);
lambda_max = lambda(51);
% i. this falls in the visible region
% ii. uv = 6.4%, vis = 48%, and ir = 45.6%
% the energy for uv = 87, vis = 565, and ir = 623
UV = L_sun(1:38);
Vis = L_sun(39:78);
IR = L_sun(79:300);
UV_Vis_IR_fig = openfig('SolarIrradiance.fig');
hold on
ar = area(lambda(1:38), UV);
ar.FaceColor = 'magenta';
ar2 = area(lambda(39:78), Vis);
ar2.FaceColor = 'green';
ar3 = area(lambda(79:300), IR);
ar3.FaceColor = 'red';
hold off
legend('L_s_u_n', 'UV', 'Vis', 'IR')
print('UV_Vis_IR.tif', '-dpng', '-r600')
saveas(gcf, 'UV_Vis_IR.fig')


%%
% Part 3.
astmg173_table = xlsread('ASTMG173.xlsx');
Wave_Length = astmg173_table(1:2002,1);
AM_0 = astmg173_table(1:2002,2);
AM_15G = astmg173_table(1:2002,3);
AM_15D = astmg173_table(1:2002,4);
PowerDensity_AM0 = astmg173_table(:,1).*astmg173_table(:,2);
PowerDensity_AM15G = astmg173_table(:,1).*astmg173_table(:,3);
PowerDensity_AM15D = astmg173_table(:,1).*astmg173_table(:,4);
openfig('SolarIrradiance.fig')
hold on

[dpb]

I get two figures but then

Error using xlsread (line 139)
XLSREAD unable to open file 'ASTMG173.xlsx'.
File 'C:\Users\...\Documents\MATLAB\Work\ASTMG173.xlsx' not found. 
>> 

Can't do anything really w/o the other data other than just put some additional random data onto the existing figure.

A Q? is why aren't you just continuing to add to the desired axis until you've got it complete as desired? Why go to the trouble of saving/loading a .fig file and trying to modify it instead? Looks like you've generated all the data here; not like you don't have something that's needed that has to come from external source.

Another Q? is what's the need for symbolic variables? Don't have here so commented out but there's nothing that seems to need in code given.

[Kyle Lazaroff]

its for the assignment i have, i have to save and alter the existing graph that way. i have to add the AM_0 etc variables to the graph against lambda over top of the existing one, and it keeps saying the error that they need to be the same length

Answer 1

[Walter Roberson]

fig = openfig('SolarIrradiance.fig');
existing_line = findobj(fig, 'type', 'line');
ax = ancestor(existing_line, 'axes');
lambda = existing_line.XData;

hold(ax, 'on');
plot(ax, lambda, AM_0, 'DisplayName', 'AM 0' );
plot(ax, lambda, AM_15G, 'DisplayName', 'AM 15 G');
plot(ax, lamda, AM_15D, 'DisplayName', 'AM 15 D');
hold(ax, 'off');
drawnow();

saveas(fig, 'SolarIrradiance.fig');

[Kyle Lazaroff]

that still gives this error,

Error using plot

Vectors must be the same length.

Error in Final_Project (line 68)

plot(ax, lambda, AM_0, 'DisplayName', 'AM 0' );

[Walter Roberson]

I would suggest to you that your AM_0 does not happen to contain exactly the same number of rows as (0.001:0.01:3)*1e-6 has elements.

If Wave_Length just happens to be the same meaning as lambda, then I would suggest that what you need is

AM_0int = interp1(Wave_Length AM_0, lambda);
AM_15Gint = interp1(Wave_Length, AM_15G, lambda);
AM_15Dint = interp1(Wave_Length, AM_15D, lambda);
plot(ax, lambda, AM_0int, 'DisplayName', 'AM 0' );
plot(ax, lambda, AM_15Gint, 'DisplayName', 'AM 15 G');
plot(ax, lamda, AM_15Dint, 'DisplayName', 'AM 15 D');

Or you might be willing to risk skipping the interpolation and instead doing

plot(ax, Wave_Length, AM_0, 'DisplayName', 'AM 0' );
plot(ax, Wave_Length, AM_15G, 'DisplayName', 'AM 15 G');
plot(ax, Wave_Length, AM_15D, 'DisplayName', 'AM 15 D');

The difficulty with this is that Wave_Length might have a different range than lambda does.

[Kyle Lazaroff]

that would work, however Wave_Length is a different vairable tthan lambda , it was needed for the PoweDensity variables

[Walter Roberson]

Okay, for any given row of astmg173_table column 2, how do you know what the corresponding lambda value is for it?