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Create custom x-axis for 'imagesc' plot

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I am trying to create a custom x-axis for my imagesc plot using a separate vector ('xaxis') with increasing values from -150.36 to 265.8773.
However, I am facing an issue where when I set this vector as my x-axis, it appears only for half of the image. The vector 'xaxis' has the same length as the x-axis pixels in the image and I would like it's values to represent each x-axis pixel rather than the default which only has the pixel value listed.
My intention is to then evenly space out the x-axis ticks using the label command after setting the x-axis to 'xaxis' to avoid overwriting/bunching together.
Original x-axis;
x-axis from vector 'xaxis':
From the image, I understand that the ticks only go to half the image before starting over and overwriting the previous ticks.
Any tips would be highly appreciated.
Below is my code for setting the x-axis to the desired tick values;
colormap gray;
ax = gca;
ax.XTick = [xaxis];


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Accepted Answer

Star Strider
Star Strider on 4 Jul 2020
Much of your code is ‘over the horizon’ and so out of sight.
Try something like this:
x = 0:500; % Create Data
y = randn(size(x)); % Create Data
plot(x, y)
xt = get(gca, 'XTick'); % Original 'XTick' Values
xtlbl = linspace(-150.36, 265.8773, numel(xt)); % New 'XTickLabel' Vector
set(gca, 'XTick',xt, 'XTickLabel',xtlbl, 'XTickLabelRotation',30) % Label Ticks
I know you are displaying an image, not data, however this should work. Note that you need to define the location of the x-tick labels with respect to the original x-tick values. They do not have to be the actual x-tick values (as I use here), however they must be within that range.
Something like this would also work:
xtnew = linspace(min(xt), max(xt), 5); % New 'XTick' Values
xtlbl = linspace(-150.36, 265.8773, numel(xtnew)); % New 'XTickLabel' Vector
set(gca, 'XTick',xtnew, 'XTickLabel',xtlbl) % Label Ticks
Note that ‘xtnew’ spans the original ‘xt’ range. It just defines them differently.


Kevin Mutai
Kevin Mutai on 4 Jul 2020
Hi Star Strider (cool name by the way), thanks for the tip. It worked great!
Star Strider
Star Strider on 4 Jul 2020
As always, my pleasure!
Thank you!

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More Answers (1)

Image Analyst
Image Analyst on 4 Jul 2020
If you use imshow(), you can simply pass in the endpoints of the x axis to the 'XData' property:
imshow('moon.tif', 'XData', [-150.36, 265.8773]);


Kevin Mutai
Kevin Mutai on 4 Jul 2020
Hi Image Analyst. Thanks for the tip, I think this would work but as I am not too familiar with imshow(), is it possible to make it plot out from an array similar to imagesc()?
Image Analyst
Image Analyst on 4 Jul 2020
Of course:
imshow(inclinedCyl_d20, [], 'XData', [-150.36, 265.8773]);
Kevin Mutai
Kevin Mutai on 4 Jul 2020
Wonderful, thanks for the tip. This works too.

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