Filled contour plot colormap

Dear MATLAB users,

I would like to plot 3D data as a contour plot but struggle with colorbar/colormap settings.

Using R2017a, following code creates a filled 2D contour plot but for z =0 it assigns same color as for z=1.

[X,Y] = meshgrid(0:0.5:10);
Z = X + Y;
z_int=fix(Z/2);
max_z_int=max(max(z_int));
min_z_int=min(min(z_int));
contourf(X,Y,z_int,max_z_int-min_z_int);
colormap(parula(max_z_int-min_z_int))
c=colorbar;
caxis([min_z_int max_z_int])

If I add an extra color:

colormap(parula(max_z_int-min_z_int+1))

I get different colors on z=0 and z=1 but colorbar ticks are off

so I changed

 caxis([min_z_int-1 max_z_int])

but I get again same color on level z=0 and z=1...

Answer 1

[Star Strider]

Tell contourf to use more colours —

Levels = hcf.LevelList

colormap(parula(numel(Levels))

and the individual patches become distinct —

[X,Y] = meshgrid(0:0.5:10);
Z = X + Y;
z_int=fix(Z/2);
max_z_int=max(max(z_int));
min_z_int=min(min(z_int));
[~,hcf] = contourf(X,Y,z_int,max_z_int-min_z_int, 'ShowText','on');
Levels = hcf.LevelList

Levels = 1×11

0 0.9091 1.8182 2.7273 3.6364 4.5455 5.4545 6.3636 7.2727 8.1818 9.0909

colormap(parula(max_z_int-min_z_int))
c=colorbar;
caxis([min_z_int max_z_int])
colormap(parula(numel(Levels)))

.

[Carles]

Thanks Star Strider for your interest in my question.

With your code is getting better but in fact I realise that as I want the plot to show diferent number of layers, my colorbar should look like below (number of layers and tick in the middle of the color).

[Star Strider]

My pleaseure.

That is a different problem not mentioned in the original Question (that I fuly solved).

Try this —

[X,Y] = meshgrid(0:0.5:10);
Z = X + Y;
z_int=fix(Z/2);
max_z_int=max(max(z_int));
min_z_int=min(min(z_int));
[~,hcf] = contourf(X,Y,z_int,max_z_int-min_z_int, 'ShowText','on');
Levels = hcf.LevelList;
colormap(parula(max_z_int-min_z_int))
c=colorbar;
c.Ticks = linspace(0, 10, 12)+0.5;                          % Tick Locations
TickLabelVector = linspace(0, 10, 11);                      % Numeric Labels
c.TickLabels = compose('\\it\\bf%g\\rm',TickLabelVector);   % Create Tick Label Cell Array
C.FontName = 'Engravers MT';                                % Choose Font (Not All Are AVailable Here)
caxis([min_z_int max_z_int])
colormap(parula(numel(Levels)))

The online Run feature doesn’t have all the fonts that might be desired, however this demonstrates everything else with respect to the colorbar tick locations and labels, that are as requested.

.

[Carles]

Very appreciated.

Thank you so much for your time on this!

[Star Strider]

My pleasure!

If my Answer helped you solve your problem, please Accept it!

.