MATLAB Answers


how to smooth scatter plots like excel?

Asked by Shadi
on 29 Apr 2013

I'd like to plot a set of simple data with a 'smooth curve' just as excel does. I can use matlab's "scatter(x,y)' feature but I'd like to have the data points connected. Can anyone help?


It's not posible using "scatter". you could test another.

do you mean 'plot(x,y,'-*')' ?


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1 Answer

Answer by Image Analyst
on 29 Apr 2013

You could try splines, like in my demo:

% Demo to show spline interpolation.
close all; 
clear all; 
workspace; % Display workspace panel.
% Plot the original points.
x = 1:10;
y = rand (10,1);
% Plot it and show how the line has sharp bends.
plot(x, y, '-sr', 'LineWidth', 2);
set(gcf, 'Position', get(0,'Screensize')); % Maximize figure.
% Use splines to interpolate a smoother curve
% that goes exactly through the same data points.
samplingRateIncrease = 10;
newXSamplePoints = linspace(1, 10, 10 * samplingRateIncrease);
smoothedY = spline(x, y, newXSamplePoints);
hold on; % Don't destroy the first curve we plotted.
% Plot smoothedY and show how the line is
% smooth and has no sharp bends.
plot(newXSamplePoints, smoothedY, '-ob');
title('Spline Interpolation Demo', 'FontSize', 20);
legend('Original Points', 'Spline Points');
% Mathworks Demo code from their Help
% x = 0:10;
% y = sin(x);
% xx = 0:.25:10;
% yy = spline(x,y,xx);
% plot(x,y,'o',xx,yy)


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