MATLAB: How to display the numerical values of each cell as text in the PCOLOR plot

MATLABnumberspcolorshowtext;values

I am creating plots using PCOLOR. In addition to the colored cells representing the values I would also like to display the numerical value in each element of the PCOLOR plot.

Best Answer

The ability to systematically plot matrices as text cells is not available in MATLAB. It is possible to include labels and comments in plots using TEXT or ANNOTATION commands. However the creation of the plot will be very slow if you are using this on large data sets.

See the following example to get an idea how this could be implemented:

%create the PCOLOR plot
matrix=(rand(5));
pcolor(1:5,1:5,matrix);
colorbar;
%prepare position and size of textboxes
pos=get(gca,'position');
[rows,cols]=size(matrix);
width=pos(3)/(cols-1);
height =pos(4)/(rows-1);
%create textbox annotations
for i=1:cols-1
      for j=rows-1:-1:1                annotation('textbox',[pos(1)+width*(i-1),pos(2)+height*(j-1),width,height], ...
       'string',num2str(matrix(j,i)),'LineStyle','none','HorizontalAlignment','center',...
       'VerticalAlignment','middle');
      end
end

The estimation of the text values assumes you are using flat shading. This means each element has a constant color determined by the color value at the endpoint of the segment or the corner of the face that has the smallest index or indices. If you are not using flat shading you have to adjust the example accordingly.

Related Solutions

MATLAB: Pcolor – how to remove NaN text / string

Dear all I found a solution, I just simply delete any string that contains NaN. See updated code below:

figure
H = pcolor(xedges,yedges,Ab);
colormap(cm);
set(H, 'linestyle', 'none');
pos=get(gca,'position'); % get plot position
[rows,cols]=size(Ab); % get cols and rows size
width=pos(3)/(cols-1); % get width and height postions
height =pos(4)/(rows-1);
%create textbox annotations
for i=1:cols-1 
      for j=rows-1:-1:1;
      annotation('textbox',[pos(1)+width*(i-1),pos(2)+height*(j-1),width,height], ...
      'string',num2str(Ab(j,i)),'LineStyle','none','HorizontalAlignment','center',...
      'FontSize',10,'FontWeight','Bold',...
      'VerticalAlignment','middle');
      end
end
delete(findall(gcf,'String','NaN')); % delete the annotation
set(gca,'Xlim',[0 30]); 
set(gca,'XTick',[0:3:30]);
set(gca,'Ylim',[0 5]);
set(gca,'YTick',[0:1:5]);
set(gca,'FontSize',10,'FontWeight','Bold');

Cheers, Raydo

MATLAB: How to add and arrange a text in a plot using commands

It's hiding in the annotation command.

h = annotation('textbox')

After you've created it, you can use the set command to change things.

set(h,'String','Something or other')
set(h,'Position',[.3 .8 .4 .1])
set(h,'HorizontalAlignment','center')

You can also pass those sets into the annotation command:

annotation('textbox','String','another one','FontSize',24)

Best Answer

Related Solutions

MATLAB: Pcolor – how to remove NaN text / string

MATLAB: How to add and arrange a text in a plot using commands

Related Question