Controlling the order of points when using "pline"

Hey guys,

Kind of a beginner here.  But I have a planar (x,y )surface divided into a bunch of points.  I am sampling an image with these points.  And depending on certain values in the image, each points 'Z' value changes.  I have all of this working.  I deconstruct the points, and reconstruct them with the existing x,y points, and the new z points from the image.

Now I want to create a line that goes through the points.  When I simply feed them into a "pline" component, it goes linearly by each row that the original surface was divided into.  However, I want the line to move through the points going from the lowest point in z-direction to the highest.

Any suggestions

Thanks

ew