# How to plot A Curve That Connects The Highest Values in Y-Axis

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Yaser Khojah on 26 Apr 2019
Edited: Yaser Khojah on 29 Apr 2019
Can anyone please help me to create the curve as below. I'm looking for away to plot the highest point at y-axix for all x-axis. I attached my data and plot as below.
scatter(MaT_All(:,18), MaT_All(:,17))
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Yaser Khojah on 26 Apr 2019
Dear darova,
I want to focus on the top part only and I need to extract these data to do more analyse.

Naman Bhaia on 29 Apr 2019
Hello Yaser,
I believe the issue you are facing can be solved in two steps:
1. Find the maximum value corresponding to each value of x. For this, you can visit this MATLAB Answer thread and see if it helps.
2. Plot the values found in the previous step to form the upper boundary .
Yaser Khojah on 29 Apr 2019
Dear Naman, I have looked into it but I have one question as my code below. How to find the index of the ymax?
x = round(MaT_All(:,18),0);
y = MaT_All(:,17);
[uv,~,idx] = unique(x);
ymax = accumarray(idx,y,[],@max); %build matrix
figure
scatter(uv,ymax)
line(uv,ymax)
I alost tired the following and I still need to find the index of (Resutl)
Result = splitapply(@max, y, idx);
figure
scatter(uv,Result)
line(uv,Result)