Attached are the plots of a i get from a csv file imported to MATLAB. I want to declutter the plot (remove the noise captured by measuring instrument) zoom on in the data.

Desired result capture.png

Answer 1

[Kevin Holly]

open('untitled2.fig')
xlim([-0.5 2.5]) % changed domain min and max to zoom in.

h=gca; % obtained handle of the current axes
x = h.Children.XData; % extracted xdata from figure
y = h.Children.YData; % extracted ydata from figure
y=lowpass(y,10,1000); % Low pass filter with cut off at 10Hz, assuming sample rate of 1000 Hz 
plot(x,y)
xlim([-0.5 2.5]) % changed domain min and max to zoom in.

open('untitled.fig')

h=gca; % obtained handle of the current axes
x = h.Children.XData; % extracted xdata from figure
y = h.Children.YData; % extracted ydata from figure
y=lowpass(y,10,1000); % Low pass filter with cut off at 10Hz, assuming sample rate of 1000 Hz 
figure
plot(x,y)
xlim([-20 20])

[Kevin Holly]

Now, if you want to just update the figures:

open('untitled2.fig')
xlim([-0.5 2.5]) % changed domain min and max to zoom in.
h=gca; % obtained handle of the current axes
y = h.Children.YData; % extracted ydata from figure
y=lowpass(y,10,1000); % Low pass filter with cut off at 10Hz, assuming sample rate of 1000 Hz 
h.Children.YData = y;

open('untitled.fig')
h=gca; % obtained handle of the current axes
y = h.Children.YData; % extracted ydata from figure
y=lowpass(y,10,1000); % Low pass filter with cut off at 10Hz, assuming sample rate of 1000 Hz 
h.Children.YData = y;
xlim([-20 20])

[Sarthak Jakar]

Hi @Kevin Holly

Can you please also tell how do i identify what part of data from the csv contribute to this plot?

Since there are 100000 reading taken in the csv file, i need to know what data points are contributing to the plot. so that i can extract that in to other excel file and do further calculation.

[Kevin Holly]

I read the data from the figure that you provided.

open('untitled2.fig')
xlim([-0.5 2.5]) % changed domain min and max to zoom in.
h=gca; % obtained handle of the current axes
y = h.Children.YData; % extracted ydata from figure
y=lowpass(y,10,1000); % Low pass filter with cut off at 10Hz, assuming sample rate of 1000 Hz 
h.Children.YData = y;

You can find out the datapoints at the x limits I chose with the following:

x = h.Children.XData; % extracted ydata from figure
startpoint = find(x==-0.5)

startpoint = 49380

endpoint = find(x==2.5)

endpoint = 52380

From the data in our plot, I created the following plot from 49380 to 52380

plot(x(startpoint:endpoint),y(startpoint:endpoint))

[Sarthak Jakar]

@Kevin Holly okay got it, thanks..then i can use xlxwrite to save the start and end data point range in excel, right?

[Kevin Holly]

Yes, you could use xlswrite to save the data within that range.

new_x = x(49380:52380);
new_y = y(49380:52380);

You can save the variables new_x and new_y into the Excel sheet.

[Sarthak Jakar]

Ok thanks Kevin..you saved my day.