how to change colorbar's color to continuous

Hi, I generated the following plot:

But the colorbar ticks are not corresponds to each color. For example, 2 is inside of one color. Is it possible to change the colorbar to continuous?

Also, my matrix does not have negative values. I would like to use more levels of red colors to describe my data and only one level of blue for show negative.

Here is my code:

A=readtable('data.csv');
B=table2array(A(:,2:end));
heatmap_obj=HeatMap(B,'Colormap',redbluecmap)
h=plot(heatmap_obj)
hcb=colorbar(h);

Data is attached.

Answer 1

[Ameer Hamza]

This is happening because you are using matrix redbluecmap as the color map, and this matrix only contains 11 colors. Either run the code with default colormap like this

heatmap_obj=heatmap(B)

or increase the number of colors in redbluecmap.

Edit:

the final code after discussion in comment is:

A=readtable('data.csv');
B=table2array(A(:,2:end));
cmap = redbluecmap;
newCmap = imresize(cmap, [64, 3]);  % original color map contain just 11 colors, this increase it to 64
newCmap = min(max(newCmap, 0), 1);
heatmap_obj=HeatMap(B,'Colormap', newCmap);
h=plot(heatmap_obj);
hcb=colorbar(h);

[Ameer Hamza]

@Li Xue's answer moved here

If I run

    heatmap_obj=HeatMap(B)

It will generate a black-red plot. I still want to use several levels of red to describe my positive data and blue for negative. How can I do that? Thanks a lot.

[Ameer Hamza]

Are you using heatmap() (all lowercase) which is MATLAB builtin function or HeatMap() which you have defined yourself?

[Li Xue]

I used the matlab HeatMap (two capitals): https://nl.mathworks.com/help/bioinfo/ref/heatmap.html

[Ameer Hamza]

I didn't realize you are referring to Bioinformatics Toolbox, Try this code now

A=readtable('data.csv');
B=table2array(A(:,2:end));
cmap = redbluecmap;
newCmap = imresize(cmap, [64, 3]);  % original color map contain just 11 colors, this increase it to 64
newCmap = min(max(newCmap, 0), 1);
heatmap_obj=HeatMap(B,'Colormap', newCmap);
h=plot(heatmap_obj);
hcb=colorbar(h);

[Li Xue]

It looks great! Many thanks.

[Ameer Hamza]

You are welcome.