Need help. I want to read the topography file into MATLAB as an array and make an image?

Hello Matlab experts,

How do I read the topography file into MATLAB as an array and make an image? Can I make an illuminated image by using the Matlab function diff()?

Thank you.

[Star Strider]

‘Can I make an illuminated image by using the Matlab function diff()?’

No, but you can subtract adjacent elements of it that way.

[Walter Roberson]

What file format is the topography file in?

diff() is not typically useful for making an illuminated image, I would think, but I am not sure what sense of "illuminated" you mean here?

[JC]

I've read the file using the following codes. How do I tell what file format I'm dealing with for the topo file? maybe the codes below help?

This is the file: http://topex.ucsd.edu/rs/labs2019/lab3/lajolla_swab

 fid=fopen('lajolla_swab','r');
 topo=fread(fid,[3240,1440],'int16')';

[JC]

Not sure if this would work? I also want to set the limits of the imagesc plot to [-1000,1000].

-----------------------------------------------------------------------------------------------------

load the topography image into matlab
%
   fid=fopen('lajolla_swab','r');
   topo=fread(fid,[3240,1440],'int16')';
% 
% image the topography
%
imagesc(topo);
xlabel("x-axis")       
ylabel("y-axis")
title("Topography of La Jolla Shores")
%
% illuminate the topography
%
diff(topo) 

[Walter Roberson]

The first part might work. The diff() does not appear to be me to be doing anything useful.