MATLAB Answers


Problem when plotting a matrix

Asked by Yixin Shao on 20 Feb 2019
Latest activity Commented on by Yixin Shao on 26 Feb 2019
When I use the 'imagesc' function to plot the image with scaled colors, the value on the y coordinate always goes from the min to max from top to bottom, which makes the figure very weird..
I want the y axis to start from 0 to 1, as we usually labelled it..
But even if I get the bottom half and inverse the sequence in my 'Y'(so it goes from 0 to 1), but when plotted, it will again always label it from the min to max from top to bottom... is there any ways I can fix it?
f1 = figure;
title('Dispersion M_x');
xlabel('k_x', 'FontSize', 30);
ylabel('f/Hz','FontSize', 30);
set(gca, 'FontSize', 20);
saveas(f1, [sname 'Mx'], 'png');


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1 Answer

Answer by Agnish Dutta on 26 Feb 2019
Edited by Agnish Dutta on 26 Feb 2019

From what I understand, you want to plot the values of 'abs(log(Z1shift))' matrix in a particular range.
imagesc(x,y,C) specifies the image location. Use x and y to specify the locations of the corners corresponding to C(1,1) and C(m,n). To specify both corners, set x and y as two-element vectors. To specify the first corner and let imagesc determine the other, set x and y as scalar values. The image is stretched and oriented as applicable.
Refer to the following link for more information:

  1 Comment

I know, but usually, when you plot something, you what the value increase from origin in y-axis, but when you use imagesc, no matter how you set the "Y", the value will always be adjusted to go from small to large from top to bottom(as I showed, from -1 to 1), which is usually not what we want.

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