Vectors autoscaling

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Bianca Bianca
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Vectors autoscaling

Hello everyone,
I was wondering whether the "autoscale" option (Plot -> Modify plot appearance -> Vector scale) showed the effective movements of the pixels in the images (scale 1:1) or if it was just a function implemented to automatically rescale vectors so they do not overlap.

Thank you for your time in advance!
William William
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Re: Vectors autoscaling

Hi,
Autoscale enables the Matlab built-in autoscale of the quiver plot. The absolute vector length does not have a meaning in PIVlab. It depends on many things, including screen resolution, DPI etc...

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Bianca Bianca
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Re: Vectors autoscaling

Thank you for your time and answer!
So (just to be sure I got it right) even by setting the magnification to 1 ("vector scale") the vectors displayed at the end of the analysis wouldn't match the actual interrogation areas displacement, is this correct?
Again, thank you in advance!
William William
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Re: Vectors autoscaling

Hi Bianca,
yes, you are right. You can check the effect by plotting directly in Matlab:

[x,y]=meshgrid(1:10:100,1:10:100);
quiver(x,y ,ones(10,10),zeros(10,10),'autoscale','off'); %plots with a magnification factor of one

Please consider donating for the PIVlab project:
http://paypal.me/pools/c/81Y8wBVi4y

The developer needs to update to a recent Matlab release in order to keep the project running.