How to selected a variable point on the y-axis?

I've got 5 subjects who walk up the stairs. And I want to select the starting point for each subject. The starting point on the y-axis. The y-axis gives the distance. (look figure).

Answer 1

[Joseph Cheng]

well there isn't a figure in your question. But a quick assessment would say you have some equation that would be distance = stair climb rate * time + constant. where your constant would be the initial stair position. you can use the rand() or randi() functions to generate your starting points

[Sam]

could you explain rand and randi please?

Answer 2

[Image Analyst]

How about using ginput() to let the user specify the starting points?

[Sam]

I used ginput to select 2 datapoints. But the problem is that there are 5 subjects which each are measured minimum 4 times... So that are 20 figures... That a lot of clicking for the user. So I was looking for solutions to select datapoints without using ginput().

[Image Analyst]

Hard to say since you're making us work blind. Maybe just select 2 and put the remaining three on a line extrapolated from the first two????