How to plot quivers only on pixels with an intensity greater than 0?

I am trying to quantify the direction of my quiver plot, but quivers stemming from pixels with an intensity of 0 tend to skew the data. Therefore, I want to stop quivers from being plotted on pixels with an intensity of 0.

Answer 1

[Cris LaPierre]

quiver will not plot nan, so a simple solution may be to replace any value of 0 with nan.

U(U==0)=nan;
V(V==0)=nan;
quiver(X,Y,U,V)

[Flint Marko]

Hi Cris, thank you for your suggestion. I have tried this, but unfortunately the U and V of black pixels bordering my ROI created by a mask is usually pretty high, so I can't get rid of them by using nan. This is because my code generates the quivers on each pixel based on the difference from one pixel intensity to the next. Therefore, the black pixels(0) bordering the mask will have relatively high U and V values because of the drastic change in intensity as it goes from the 0 of the background to the 10+ intensity of the ROI.

[Cris LaPierre]

That was an example of how to get quiver to not draw vectors that met some underlying condition. You can use the variable containing intensity values (which should be the same size as U and V).

U(intensity==0)=nan;
V(intensity==0)=nan;
quiver(X,Y,U,V)

[Flint Marko]

Your suggestion worked! Thanks for the help.