MATLAB: How to make a plot smooth

smooth line plot

I have attached the fig. file of the plot and I want to make the lines smooth without running code again as it takes too much time.

Best Answer

It depends on what you intend by ’smooth’.

Try this:

I = openfig('scma25.fig');
Ax = gca;
Lines = findobj(Ax,'Type','line');
for k = 1:numel(Lines)
    X(k,:) = Lines(k).XData;
    Y(k,:) = Lines(k).YData;
    pv(:,k) = polyfit(X(k,:), Y(k,:), 3);
    yf(k,:) = polyval(pv(:,k),X(k,:));
end
figure
semilogy(X', yf')
grid
legend(Ax.Legend.String)
xlabel(Ax.XLabel.String)
ylabel(Ax.YLabel.String)

It uses polyfit and polyval to fit your data, then plots the fitted data in a new figure. It also re-uses your axis labels and legend strings.

Related Solutions

MATLAB: How to use spline for a fig. file

Try this:

I = openfig('fft scma 25.fig');
Ax = gca;
lgnd = Ax.Legend;
Lines = findobj(Ax,'Type','line');
N = 5;                                                              % Interpolation Points Length Multiplication
for k = 1:numel(Lines)
    X(k,:) = Lines(k).XData;
    Y(k,:) = Lines(k).YData;
    xq(k,:) = linspace(min(X(k,:)),max(X(k,:)), numel(X(k,:))*N);   % Interpolation Points Vector
    ys(k,:) = spline(X(k,:),Y(k,:),xq(k,:));                        % Spline Fit To Data
end
figure
semilogy(xq', ys')
grid
legend(Ax.Legend.String)
xlabel(Ax.XLabel.String)
ylabel(Ax.YLabel.String)

Change ‘N’ to get the result you want.

This is essentially the same as my previous code, this time doing a spline interpolation.

EDIT —

Corrected typographical error. Code unchanged.

MATLAB: Where are the data

Try this:

F = openfig('untitled.fig');
ax = gca;
lines = findobj(ax, 'Type','Line');
for k = 1:numel(lines)
    x{k,:} = lines(k).XData;
    y{k,:} = lines(k).YData;
end

The x- and y-data for each line are in their appropriate cell arrays.

Best Answer

Related Solutions

MATLAB: How to use spline for a fig. file

MATLAB: Where are the data

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