How can I adjust the colorbar scale in my contour plot?

I have a contour plot with a colorbar that is showing as all one color. I would like to adjust the plot so that the colors have more variation to better show the changes in the plot. Below is a screenshot of my contour plot,

And here is an example of what I'd like it to look like.

Below is my code. I've tried a lot of different things, but I'm not very strong in Matlab and could not figure out where I'm going wrong. Any help is appreciated!

for i = 1:100
    velocity_grid_gw(i,:) = ((mu_w/mu_gw)*(u_surface/(h+((mu_w/mu_gw)*d)-d))).*y_gw(i); %m/s
    velocity_grid_w(i,:) = (u_surface/(h+((mu_w/mu_gw)*d)-d)).*y_w(i)+u_surface-(u_surface/(h+((mu_w/mu_gw)*d)-d))*h; %m/s
end

Unrecognized function or variable 'mu_w'.

fontsize = 16; %font size for plotting

figure
imagesc(x_gw,y_gw,velocity_grid_gw);
hold on
imagesc(x_w,y_w,velocity_grid_w);
hold off
xlabel('$x$ (m)','Interpreter','Latex','FontSize',fontsize);
ylabel('$y$ (m)','Interpreter','latex','FontSize',fontsize);
set(gca,'YDir','normal')
grid on
cbar = colorbar('peer',gca);
set(get(cbar,'title'),'String','$u$ (m/s)','Interpreter','Latex','fontsize',fontsize)
set(gca,'fontsize',fontsize)

[Walter Roberson]

Note that the color scaling is going to be determined by min(min(velocity_grid_gw(:)),min(velocity_grid_w(:))) and the corresponding max() . The color scaling is not going to be determined individually for velocity_grid_gw and velocity_grid_w

[Image Analyst]

Your code does not work. Please provide a working example (how did you get your plots?). Why are you trying to show one image on top of another without setting the opacity/transparency?

If you have any more questions, then attach your data and code to read it in with the paperclip icon after you read this:

TUTORIAL: How to ask a question (on Answers) and get a fast answer

[Walter Roberson]

@Image Analyst

We do not know that the images are overlayed. The two imagesc calls use different variables for XData and YData, so potentially those variables are configured so that the images are side by side. Maybe.

Answer 1

[Epsilon]

Hi Eleanore,

The color scaling should be automatically done based on the range of data in velocity_grid_gw and velocity_grid_w .

Still the colormap limits can be changed using 'clim' for better visual clarity. Attaching an exapmle code below:

gm = linspace(0, 0.1, 100)'; 
gm = repmat(gm, 1, 100); 

imagesc(gm);
% Colormap limits between 0 to 1
clim([0 1]);

colorbar;
xlabel('X-axis');
ylabel('Y-axis');

imagesc(gm);
% Colormap limits between 0 to 0.1
clim([0 0.1]);

colorbar;
xlabel('X-axis');
ylabel('Y-axis');

Documentation link to clim (caxis in releases before R2022a): https://www.mathworks.com/help/matlab/ref/clim.html

Hope it helps!

[Eleanore]

Thank you very much!