Plotting Grayscale from .csv with colorbar restriction

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Jaslyn Tan
Jaslyn Tan 2019-10-24
回答： Jaslyn Tan 2019-11-12
Hi there,
Can anyone please help..? I have grayscale image data in a .csv file I need to plot. The values in the .csv are the z values that I wish to plot as an image, the x and y coordinates of the z values in the file represent the location of that pixel in the image.
I need to restrict the colorbar to say 0 to 0.5 to see the detail in the certain part of the image. Everything below 0 can be black, above 0.5 can be white, but I need 0-0.5 to be greyscale.
I have plotted using the following code but what I get is a mostly blank image.
Please can someone help? I attach the data and my plot.
filename = 'C:\\my data.csv';
M = csvread(filename)
J = contourf(M)
colormap gray
h = colorbar;
set(h, 'ylim', [0 0.5])

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采纳的回答

Jaslyn Tan
Jaslyn Tan 2019-11-12
In the end I used this:
filename = 'C:\\my data.csv';
M = csvread(filename)
clims = [0 1];
J = imagesc(M,clims)
colormap('jet')
Thank you so much for your help!

更多回答（1 个）

Walter Roberson
Walter Roberson 2019-10-24
caxis([0 0.5])
  1 个评论
Jaslyn Tan
Jaslyn Tan 2019-10-27
Thank you so much! But
filename = 'C:\\my data.csv';
M = csvread(filename)
J = contourf(M)
colormap gray
caxis([0 0.5])
only changes the scale bar, the image is still all black. Am I doing this wrong..? Thank you in advance.

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