How to put a title on a colorbar?

I have a 3D surface surf(X,Y,Z) viewed from view(0,90) with a colorbar which I want to put a title on. The help instructions talk about an lcolorbar, TitleString and ZlabelString but there's no example and I'm lost.

[X Y]=meshgrid(0:100,0:100);

Z=Y;

surf(X,Y,Z);

view(0,90);

hcb=colorbar;

?????? what next to put a title on the colorbar please ?????

Maybe something like set(get(hcb,'Title'),'cb title') but I wouldn't be asking if that worked ...

Thanks.

[denny]

hcb=colorbar

title(hcb,'title')

Answer 1

[Jonathan LeSage]

Using the handle for the colorbar (in your case, the variable hcb), you can locate the colorbar handle title using the get function. Once you've found the handle for the colorbar title, you can directly change the title string via the set function. When working with figures in MATLAB, you'll often find yourself referencing graphic handles, so I recommend brushing up on them!

• http://www.mathworks.com/help/matlab/learn_matlab/understanding-handle-graphics-objects.html;jsessionid=b8f70138991861209dd89f7d8f23
• http://www.mathworks.com/help/matlab/ref/get.html

In your case, you can change the colormap title with just a few lines of code! Here is an example, which you can add after your example code above, to get you started:

colorTitleHandle = get(hcb,'Title');
titleString = 'A title';
set(colorTitleHandle ,'String',titleString);

Hope this clarifies things a bit!

[Daniel Lyddy]

I tried this, and it didn't seem to work at first, but ...

I use 'colordef black' for my default figure color palette, which I set in my startup.m file. In spite of that, the sequence of commands that Jonathan gives will produce a colorbar title whose 'Color' property is [0 0 0], aka black. So, in order to actually see the colorbar title in my case, I have to do:

set(colorTitleHandle, 'Color', [1 1 1]);

Note that if you use 'colordef white' the above command will make your title disappear into the whiteness around it.

Answer 2

[Ross]

Thanks Jonathan, you got me over the line. I prefer implementing your recommended approach in one line:

set(get(hcb,'Title'),'String','A Title')

From your solution I see I have to tell the compiler I'm actually giving it a 'String' for the Title and I don't understand why I should need to do that but OK.

The other thing is I don't know why the help doesn't mention the colorbar 'Title' field at all (I found it by guesswork looking through all the the colorbar fields) yet does talk about TitleString and ZlabelString which don't seem to exist at all.

[Mitsu]

For future reference, you are not telling the compiler that you are giving it a "String".

If you run

hcb = colorbar;
hcb.Title

you will see that "Title" is not string variable, but rather contains a bunch of property: font size, font weight, color, etc. Among these, the name for the property that actually contains the text is called "String".

Hence,

hcb.Title.String = "A Title";

...will have the same effect.

Answer 3

[Mitsu]

Alternatively,

hcb=colorbar;
hcb.Title.String = "A Title";

Among the properties of "hcb" there is "Title", which is a Text data type that again contains properties regarding the content of the text (the "String"), formatting, location, etc.

Note the variable type of each part:

>> class(hcb)
ans =
    'matlab.graphics.illustration.ColorBar'

>> class(hcb.Title)
ans =
    'matlab.graphics.primitive.Text'

>> class(hcb.Title.String)
ans =
    'char'