How can I fix the number of ticks in a colorbar, without depending on the values?

Question

Diana 2016-11-17

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/312683-how-can-i-fix-the-number-of-ticks-in-a-colorbar-without-depending-on-the-values

评论： Adam 2016-11-17

Is there any way to set the number of ticks in a colorbar? I mean whatever the values are, I want always 5 ticks in the colorbar.

I have tried something like cbr = colorbar L = get(cbr,'YLim'); set(cbr,'YTick',linspace(L(1),L(2),5))

and then using either ceil or floor, but it generates numbers that do not look nice like 1000, 2000, 3000, but instead 1232, 2464, 3696, etc...

Any idea on how to fix this???

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Adam 2016-11-17

在 MATLAB Online 中打开

You can either have linearly space ticks or you can define the number of ticks, you can't have both for an arbitrary data range of you want to include the extreme values.

I wrote a function to create axes ticks with values that looked user friendly, but it is 70 lines long and I'm still not always happy with its results, especially if I force it to include the end values.

Ultimately it is just defining the maths you want for your tick values though. If you don't care about spacing or how far they stretch then obviously you can code:

set( cbr, 'YTick', 1000:5000 )

to simply get 5 ticks with nice values on!

I defined my

acceptableTickMultiples = [1 2 2.5 5 7.5 10];

and a desired number of ticks then used some base 10 logarithms on my data range to determine the best set of ticks to fit my constraints, though in my case my desired number of ticks was just advisory and the algorithm aims somewhere close to that.

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Adam 2016-11-17

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/312683-how-can-i-fix-the-number-of-ticks-in-a-colorbar-without-depending-on-the-values#answer_243657

在 MATLAB Online 中打开

figure; hAxes = gca;
imagesc( hAxes, magic( 20 ) )
h = colorbar;
colourRange = caxis( hAxes );
h.Ticks = linspace( colourRange(1), colourRange(end), 5 );

The results look ridiculous in that example, but it does what you require and you can define your 5 ticks in any way you please. Defining a fixed number of human-friendly ticks for an arbitrary data range is always a tricky task though, especially so if you wish to include the extrema of the range.