How can I set correctly the colorbar?

9 views (last 30 days)
I tried to set a colorbar according to the following way:
m1 = [101 255 255]./255;
m2 = [207 170 85]./255;
m3 = [255 207 0]./255;
m4= [255 255 101]./255;
m5 = [203 0 203]./255;
map=[m1;m2;m3;m4;m5];
labels={'ET'; 'BSk'; 'BWh'; 'BWk'; 'Dfc'};
h=colorbar;
set(h,'YTickMode','manual','YTick',[1:length(map)],'YTickLabelMode','manual','YTickLabel',labels);
But in the figure only 'BWk' is marked in the midle of colorbar. How can I set correctly the colorbar?

Accepted Answer

Image Analyst
Image Analyst on 7 Sep 2015
A few problems. You don't want your y tick numbers to go from 1 to 5. You want them to go from 0 - 255 or between the min and max of your image. As it is, with no data displayed, your caxis (the range) is 0 to 1, yet your tick marks go from 1 to 5. So only the one at 1 will appear - the rest are off the top of the scale and not displayed or visible. See corrected code:
imshow('cameraman.tif');
m1 = [101 255 255]./255;
m2 = [207 170 85]./255;
m3 = [255 207 0]./255;
m4= [255 255 101]./255;
m5 = [203 0 203]./255;
map=[m1;m2;m3;m4;m5];
labels={'ET'; 'BSk'; 'BWh'; 'BWk'; 'Dfc'};
colormap(map); % Apply the colormap
h=colorbar;
set(h,'YTickMode','manual','YTickLabelMode','manual');
length(map)
cMapRange = caxis();
xTickNumbers = linspace(cMapRange(1), cMapRange(2), size(map, 1));
set(h,'YTick',xTickNumbers,'YTickLabel',labels);
  2 Comments
Image Analyst
Image Analyst on 8 Sep 2015
Dfc is not missing from mine:
I don't know why it's missing from yours. Try my code or else check your code more carefully. Or maybe try resizing your figure.

Sign in to comment.

More Answers (1)

Walter Roberson
Walter Roberson on 7 Sep 2015
colorbar() uses y values that are within the caxis limits. If your caxis limits (which are usually determined automatically from your data) do not happen to include values in your tick range 1 to 5, then the corresponding label will not show up in the graph.
For example use
surf(2.1 + 2*rand(50,50));
and then your code. The data values do not include 1 or 2 or 5, so the automatic caxis limits will run from just over 2.1 to just under (2.1+2 = 4.1), leaving only the ticks 3 and 4 within the range to be drawn by colorbar, so only those two labels show up.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!