How to shade area under curve and x axis in log-log scale?

Hello!!!

I have two plots of power spectral density in log-log scale (please see the code below). I would to shade area under these two curves. Can anyone please guide me?

figure(61)

        h1=loglog(f_1(:,1),Su_1(:,2), 'color', color_plot_i...
           , 'DisplayName', legend_name_i,'linewidth',2); %% f_1 is the frequency, Su_1 is the power
    hold on
        h2=loglog(f_2(:,1),Su_2(:,2), 'color', color_plot_i...
           , 'DisplayName', legend_name_i,'linewidth',2);

      xlabel('Frequency (Hz)','fontsize',20);
      xlim([0.01 1]); 
    ylabel('Power Spectrum','fontsize',20);

     
set(gca, 'XScale', 'log', 'YScale','log')

% set unit for figure size to inches
set(gcf, 'unit', 'inches');
% get the original size of figure before the legends are added
figure_size =  get(gcf, 'position');
% add legends and get its handle
h_legend=findobj(gcf,'type','legend');
if Switch_Plot_Legend==1
set(h_legend,'Location','NorthOutside')  % legend is outside
else
set(h_legend,'Location','BestOutside')  % legend is outside
end
% set unit for legend size to inches
set(h_legend, 'unit', 'inches');
% get legend size
legend_size = get(h_legend, 'position');
% new figure width
figure_size(3) = figure_size(3) + legend_size(3);
% set new figure size
set(gcf, 'position', figure_size)

   ImageName61 = sprintf('%s%s%s','PSD_plot, '.png'); % Save the image 
print('-dpng',ImageName61,'-painters'); % Print = save
newChr61 = strrep(ImageName61,'png','fig');
savefig(newChr61);

Answer 1

[Star Strider]

It is not possible to use patch directly on a logarithmic axis scale (at least I’ve never been able to get that to work), so the only option is to plot the patch objects on a linear scale, then set the appropriate axis scales to 'log'.

Example —

x = linspace(1, 10);
y = exp(-(x-5).^2);

figure
patch([x flip(x)], [y ones(size(y))*min(y)], [1 1 1]*0.6)
set(gca, 'XScale','log', 'YScale','log')
grid

That usually works, and it worked in this example.

EDIT — Added plot image:

.

Answer 2

[Adam Danz]

Apply a patch to a loglog plot

If the curve is defined by x and y which are both row vectors,

bottom = min(ylim);  % or bottom = 0
p = patch([x,fliplr(x)], [y, repmat(bottom,size(y))], 'y')

if x and y are column vectors,

p = patch([x;flipud(x)], [y; repmat(bottom,size(y))], 'y')

See patch properties to learn how to make the patches partially transparent.

Demo

x = 1:1:20
y = 2.^x + 10; 
loglog(x,y)
hold on
bottom = min(ylim);  % or bottom = 0
p = patch([x,fliplr(x)], [y, repmat(bottom,size(y))], 'y');