How can I extract a profile from a surface?

22 views (last 30 days)
Hello everybody, I would like to extract a profile from a surface. My initial matrix is composed by a matrix (18011*3) of Longitude, Latitude and Depth values. Specifically, I'd like a function that in input takes the position of start (A) and end of my profile (B) (xa,ya,xb,yb) and in output return the position of the corresponding z in A and B {e.g. [A,B] = myfunc(xa,ya,xb,yb)}. I am new in matlab and now very desperated ... Someone can help me, please?

Answers (2)

Iddo Weiner
Iddo Weiner on 1 Feb 2017
Hi Leonardo, I hope I understood your question properly... Here's my suggestion (I worked with small made-up data):
data = rand([5,5,5]);
xA = 2; xB = 4; yA = 5; yB = 5;
zA = data(xA,yA,:); zB = data(xB,yB,:);
% initiate new arrays and use a loop to lower the dimensions:
low_zA = nan(length(zA),1);
for i = 1:(length(low_zA))
low_zA(i) = zA(1,1,i);
low_zB = nan(length(zB),1);
for i = 1:(length(low_zB))
low_zB(i) = zB(1,1,i);
% now if you want to draw each of the profiles:
hold on
ylabel('Z axis value')
Notice that I have some code duplication here. I'd generalize this example into a function before starting to work with it.
Hope this helps,
  1 Comment
Leonardo Colavitti
Leonardo Colavitti on 2 Feb 2017
Hello Iddo, thank you very much for your answer but I would like something of little different. I have an initial matrix which constitutes a curve (which easily I plot with plot3, mesh and surf). My goal is to write a function that in input has two values in space (xa,ya) and (xb,yb) while in output I would like to see a profile between x values and z(depth) that represents the interception between the curve and the plane y=0... I hope you can help me, anyway Thank you again!

Sign in to comment.

Walter Roberson
Walter Roberson on 1 Feb 2017 has it already built in (Image Processing Toolbox)
  1 Comment
Leonardo Colavitti
Leonardo Colavitti on 23 Feb 2017
Thanks for your answer, but it is not exactly what I am looking for. My function is defined by points and I think that 'improfile' evaluates the values of pixels (intensity) along a line in grey scale or RGB colors. Do you have any other idea?

Sign in to comment.


Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!