Thread Subject: Grey color of certain values in a jet colormap

Hi
I have a color plot using the colormap(jet(40)). Does anyone know if it is possible to assign the color grey to specific values of the matrix DATA, see below, and color all other values by the jet(40) colormap?

figure(1)
patch('Vertices',nodes,'Faces',elements, 'FaceVertexCData', DATA,'FaceColor','flat', 'LineStyle', 'none')
colormap(jet(40))


Thanks in advance

Best regards
Brian

"Brian Bak" <brianlvbak@gmail.com> wrote in message <hemb8s$nvd$1@fred.mathworks.com>...
> Hi
> I have a color plot using the colormap(jet(40)). Does anyone know if it is possible to assign the color grey to specific values of the matrix DATA, see below, and color all other values by the jet(40) colormap?
>
> figure(1)
> patch('Vertices',nodes,'Faces',elements, 'FaceVertexCData', DATA,'FaceColor','flat', 'LineStyle', 'none')
> colormap(jet(40))
>
You could star towards something like that by:
cmp = jet(40);
cmp(indx,:) = [1,1,1]*graylevel;
colormap(cmp)
Of course this will only set the selected entries in cmp to grey of your selected greylevel, leading to all values in the corresponding data ranges to grey. If you want to refine the selection of greyed out values I guess you'd have to use a longer colormap, but if you want a 40-long jet you could just run interp1 with method nearest to retain the number of unique colours.

HTH,
Bjeorn

"Bjorn Gustavsson" <bjonr@irf.se> wrote in message <hemcjk$g3l$1@fred.mathworks.com>...
> "Brian Bak" <brianlvbak@gmail.com> wrote in message <hemb8s$nvd$1@fred.mathworks.com>...
> > Hi
> > I have a color plot using the colormap(jet(40)). Does anyone know if it is possible to assign the color grey to specific values of the matrix DATA, see below, and color all other values by the jet(40) colormap?
> >
> > figure(1)
> > patch('Vertices',nodes,'Faces',elements, 'FaceVertexCData', DATA,'FaceColor','flat', 'LineStyle', 'none')
> > colormap(jet(40))
> >
> You could star towards something like that by:
> cmp = jet(40);
> cmp(indx,:) = [1,1,1]*graylevel;
> colormap(cmp)
> Of course this will only set the selected entries in cmp to grey of your selected greylevel, leading to all values in the corresponding data ranges to grey. If you want to refine the selection of greyed out values I guess you'd have to use a longer colormap, but if you want a 40-long jet you could just run interp1 with method nearest to retain the number of unique colours.
>
> HTH,
> Bjeorn

Hi Bjeorn

Thank you for the answer.

Can you elaborate further. I can't get it to work.

"Bjorn Gustavsson" <bjonr@irf.se> wrote in message <hemcjk$g3l$1@fred.mathworks.com>...
> "Brian Bak" <brianlvbak@gmail.com> wrote in message <hemb8s$nvd$1@fred.mathworks.com>...
> > Hi
> > I have a color plot using the colormap(jet(40)). Does anyone know if it is possible to assign the color grey to specific values of the matrix DATA, see below, and color all other values by the jet(40) colormap?
> >
> > figure(1)
> > patch('Vertices',nodes,'Faces',elements, 'FaceVertexCData', DATA,'FaceColor','flat', 'LineStyle', 'none')
> > colormap(jet(40))
> >
> You could star towards something like that by:
> cmp = jet(40);
> cmp(indx,:) = [1,1,1]*graylevel;
> colormap(cmp)
> Of course this will only set the selected entries in cmp to grey of your selected greylevel, leading to all values in the corresponding data ranges to grey. If you want to refine the selection of greyed out values I guess you'd have to use a longer colormap, but if you want a 40-long jet you could just run interp1 with method nearest to retain the number of unique colours.
>
> HTH,
> Bjeorn

Hi Bjeorn

Now I see what you mean. Do you know why i get the color black no matter what i set the value of graylevel to?

"Brian Bak" <brianlvbak@gmail.com> wrote in message
news:hemb8s$nvd$1@fred.mathworks.com...
> Hi
> I have a color plot using the colormap(jet(40)). Does anyone know if it is
> possible to assign the color grey to specific values of the matrix DATA,
> see below, and color all other values by the jet(40) colormap?
>
> figure(1)
> patch('Vertices',nodes,'Faces',elements, 'FaceVertexCData',
> DATA,'FaceColor','flat', 'LineStyle', 'none')
> colormap(jet(40))

Add grey to the end of the colormap.

colormap([jet(40); gray(1)]) % or just append [1 1 1] to jet(40)
colorbar

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Steve Lord
slord@mathworks.com
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