I have values For example. At x=0, y=6.1; x=5; y=6.02, x=10; y=5.98, x=15, y=6.02. I want to plot like
this figure by Matlab. Could you help me ? Thank you very much
MATLAB: How to plot in 2D
how to plot in 2d
Related Solutions
See this demo:
% Code to plot data, plus points interpolated in between the data.
clc; % Clear the command window.
clearvars;close all; % Close all figures (except those of imtool.)
workspace; % Make sure the workspace panel is showing.
format long g;format compact;fontSize = 22;% Make up sample data.
numOriginalPoints = 20;xOriginal = sort(100 * rand(1, numOriginalPoints), 'ascend');yOriginal = 30 * rand(1, numOriginalPoints) - 10;% Plot them
subplot(3, 1, 1);plot(xOriginal, yOriginal, 'ro-', 'LineWidth', 2);grid on;xlabel('X', 'FontSize', fontSize);ylabel('Y', 'FontSize', fontSize);title('Training Points', 'FontSize', fontSize);% Interpolate points in between, linearly from the min to the max.
numNewPoints = 100;xInterpolated = linspace(min(xOriginal), max(xOriginal), numNewPoints);yInterpolated = interp1(xOriginal, yOriginal, xInterpolated);% Plot interpolated points.
subplot(3, 1, 2);plot(xInterpolated, yInterpolated, 'bo-', 'LineWidth', 2);% Plot training points over them so we can see where they are in relation to the new points.
hold on;plot(xOriginal, yOriginal, 'ro', 'LineWidth', 2);grid on;title('Interpolated Points without Including Training Points', 'FontSize', fontSize);xlabel('X', 'FontSize', fontSize);ylabel('Y', 'FontSize', fontSize);legend('Interpolated', 'Training');% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0, 0.04, 1, 0.96]);% Note, if you want the original points included in the set of new, interpolated points,
% Add them to xInterpolated list.
subplot(3, 1, 3);xInterpolated = sort([xInterpolated, xOriginal], 'ascend');yInterpolated = interp1(xOriginal, yOriginal, xInterpolated);% Plot interpolated points.plot(xInterpolated, yInterpolated, 'bo-', 'LineWidth', 2);% Plot training points over them so we can see where they are in relation to the new points.hold on;plot(xOriginal, yOriginal, 'ro', 'LineWidth', 2);grid on;xlabel('X', 'FontSize', fontSize);ylabel('Y', 'FontSize', fontSize);title('Interpolated Points Including Training Points', 'FontSize', fontSize);legend('Interpolated', 'Training');% Enlarge figure to full screen.set(gcf, 'Units', 'Normalized', 'OuterPosition', [0, 0.04, 1, 0.96]);
With your data, my demo would become this:
% Create the original knot points.
xInitial = [1.6 1.1 .6 .1 .4 .9 1.4 1.9];yInitial = [1 1.5 2 2.5 3 3.5 4 4.5];lengthX = length(xInitial);% flip sideways so there is only 1 y for every x
x = yInitial;y = xInitial;% Plot it and show how the line has sharp bends.
plot(x, y, '-sr', 'LineWidth', 2);grid on;set(gcf, 'Position', get(0,'Screensize')); % Maximize figure.
% Use splines to interpolate a smoother curve,
% with 10 times as many points,
% that goes exactly through the same data points.
samplingRateIncrease = 10;newXSamplePoints = linspace(min(x), max(x), lengthX * samplingRateIncrease);smoothedY = spline(x, y, newXSamplePoints);% Now flip back
ySmooth = newXSamplePoints;xSmooth = smoothedY;% Plot smoothedY and show how the line is
% smooth, and has no sharp bends.
hold on; % Don't destroy the first curve we plotted.
plot(newXSamplePoints, smoothedY, '-ob');title('Spline Interpolation Demo', 'FontSize', 20);legend('Original Points', 'Spline Points');figure;plot(xInitial, yInitial, '-sr', 'LineWidth', 2);% Plot smoothedY and show how the line is% smooth, and has no sharp bends.hold on; % Don't destroy the first curve we plotted.plot(xSmooth, ySmooth, '-ob');grid on;
You can also use a Savitzky-Golay filter to smooth curves, and I attach a demo for that.
Best Answer