help-octave
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

How to plot surface using scaled axes values, not indexes


From: Terry Duell
Subject: How to plot surface using scaled axes values, not indexes
Date: Thu, 11 Apr 2013 12:14:51 +1000
User-agent: Opera Mail/12.15 (Linux)

Hello All,
This is a problem that has vexed me for a while now, and something tells me that it should be simple and straightforward, but I seem to have a mental block in getting there. I have data describing a surface profile, or longitudinal section of a surface. The surface data is elevation values (z) at constant longitudinal (x) spacing.
The data is read as follows...

fp1 = fopen("fred","r");
[num1 spac1] = fscanf(fp1,"%6f%6f","C"); % number of points, spacing
profile = zeros(2,num1); % set up array
% read
for i = 1:num1
        profile(1,i) = (i-1)*spac1; % x values
        profile(2,i) = fscanf(fp1,"%f \n","C"); % z values
end
fclose(fp1);

The real surface has width (y) with constant z at each x, for the range of y. I want to be able to visualise the surface, pretty much as per the attached image (surffltk-sm.jpg), but would like to be able to use real values for the x and y axes, as I has been done for the z axis.

That surface plot was obtained with the following...

n = 10;
y = zeros(n,num1);

for i=1:n
        for j =1:num1
                y(i,j) = profile(2,j);
        end
end
figure
surf(y)
view(30.0,30.0)

The above code snippet is simply a means of getting something viewable, I'm sure there are much better approaches.

So, what I want to be able to do, is achieve a surface plot as per example, but with x and y axes values displayed as scaled values, not as indexes as shown. I.E. x would have values j = j*spac1, and i = i*spac2, where spac2 is my real world y spacing. I have lost track of the various schemes that I have tried to achieve this, so at the risk of being embarrassed by a simple answer, could someone please set me straight?

Cheers,
--
Regards,
Terry Duell

Attachment: surffltk-sm.jpg
Description: JPEG image


reply via email to

[Prev in Thread] Current Thread [Next in Thread]