问题
I have a contour plot with data that goes from -90 to 90 degrees. for now i am using jet so I have a map that looks like this
I have been asked to change the colormap so that instead of having a gradient, I have a fixed color for each 5 degress (so I believe 36 colors). Also i was thinking of maybe having same colors for the interval [5 10] and [-10 -5], and so on if that makes sense.
My code is quite long because i have a lot of data to process, but that's part of it just so you can see what function i am using to plot this
%%
x1=data(:,5); %x location
y1=data(:,16); %y location
z1=phi*90; %angle phi
z2=gamma*90; %angle gamma
n=300; precision of grid
%Create regular grid across data space
[X,Y] = meshgrid(linspace(min(x1),max(x1),n), linspace(min(y1),max(y1),n));
figure(3);
contourf(X,Y,griddata(x1,y1,z1,X,Y),100,'EdgeColor', 'None')
%title('Variation of In-plane angle \phi')
axis equal
axis ([0 8000 0 12000])
axis off
h=colorbar;
caxis([-90 90])
set(h, 'YTick', [-90:15:90])
Does anyone know how to create this colorbar? Cheers
回答1:
Every colormap-generating function in Matlab, including jet, takes an argument that specifies how many colormap entries there should be. In your case, you want 180 / 5 = 36 discrete colors:
colormap(jet(36))
To make sure the 36 colors cover exactly the 5 degree steps, set the color axis explicitly:
caxis([-90 90])
The result looks e.g. like this:
来源：https://stackoverflow.com/questions/29262269/create-a-colormap-in-matlab