Finding Distance Between Points and a Curve

Hi All,

I have attached two plots I would like to analyze. In both of these plots, I would like to find the vertical distance between most of the points (excluding the points that are left of the curves) and the curve. As in, for each point, I would like to imagine a vertical line extending from the point to the curve, and then find the length of this line. Ultimately, I would like to have produced two column vectors, a and b, for each of the two plots, and then create one final column vector, a^2+b^2.

Does anybody have any insight as to how to do this?

Please let me know if I could provide more helpful information as well.

Thanks

[David Hill]

Do you have the equation of the curves? If you do, it would be easy.

[Adam Danz]

One approach would be

1. use min(redline), max(redline) to get the lower and upper bounds of the x values for the red line.
2. determine which scatter points are within those bounds and store their x-values and store them in a vector as xq.
3. use vq = interp1(x,v,xq) to interpolate the redline (x,y) coordinates at the new xq values to get the corresponding vq values.
4. Then subtract vq from the y values of the scatter points to get the vertical distance.

[Jonathan Pinko]

Adam Danz's approach worked perfectly.

Thank you.

[Adam Danz]

Thanks for the feedback! Sounds like you implemented it without any problems.