MATLAB Central Newsreader - coloring contour plot

coloring contour plot

Bahari — Mon, 10 Aug 2009 11:16:03 -0400

Dear All,
I want to color my contour base on value of Z, if Z<=1 the color will be white and if Z>1 the color will be light gray.
I succeed to plot the contour with the label as command below but still not success to coloring it.

[C,h]=contour(X,Y,Z);
clabel(C,h,'FontSize',10,'Rotation',0);
colormap gray

Thanks in advance for help.

Bahari

Re: coloring contour plot

Amin Bashi — Mon, 10 Aug 2009 12:44:03 -0400

Bahari
try this, userdata value is value of isolines of matrix Z
%%%%%%%%%%%%%%%%%%%%%%%%%%%%
[X,Y] = meshgrid(-2:.2:2,-2:.2:3);
Z = X.*exp(-X.^2-Y.^2);
[C,h] = contour(X,Y,Z);
set(h,'ShowText','on','TextStep',get(h,'LevelStep')*2)
h3 = findall(0,'userdata',-0.2,'type','patch')
set(h3,'EdgeColor',[0 0 0])

"Bahari " <baid69@yahoo.co.uk> wrote in message <h5ovhi$jug$1@fred.mathworks.com>...
> Dear All,
> I want to color my contour base on value of Z, if Z<=1 the color will be white and if Z>1 the color will be light gray.
> I succeed to plot the contour with the label as command below but still not success to coloring it.
>
> [C,h]=contour(X,Y,Z);
> clabel(C,h,'FontSize',10,'Rotation',0);
> colormap gray
>
> Thanks in advance for help.
>
> Bahari

Re: coloring contour plot

Bahari — Mon, 10 Aug 2009 13:12:03 -0400

Thanks Amin Bashi.

I tried your example but seem not as I expected. The background of contour is black, the label is white and the isoline is colorfull.
I'm not sure what wrong.

Regards

Bahari

"Amin Bashi" <matlabedu.ir.nospam@gmail.com> wrote in message <h5p4mj$i9b$1@fred.mathworks.com>...
> Bahari
> try this, userdata value is value of isolines of matrix Z
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%
> [X,Y] = meshgrid(-2:.2:2,-2:.2:3);
> Z = X.*exp(-X.^2-Y.^2);
> [C,h] = contour(X,Y,Z);
> set(h,'ShowText','on','TextStep',get(h,'LevelStep')*2)
> h3 = findall(0,'userdata',-0.2,'type','patch')
> set(h3,'EdgeColor',[0 0 0])
>
>
> "Bahari " <baid69@yahoo.co.uk> wrote in message <h5ovhi$jug$1@fred.mathworks.com>...
> > Dear All,
> > I want to color my contour base on value of Z, if Z<=1 the color will be white and if Z>1 the color will be light gray.
> > I succeed to plot the contour with the label as command below but still not success to coloring it.
> >
> > [C,h]=contour(X,Y,Z);
> > clabel(C,h,'FontSize',10,'Rotation',0);
> > colormap gray
> >
> > Thanks in advance for help.
> >
> > Bahari

Re: coloring contour plot

Lorenzo Guerrasio — Mon, 10 Aug 2009 13:27:02 -0400

You could simply create your colormap and than load it everytime you make a figure.

"Bahari " <baid69@yahoo.co.uk> wrote in message <h5ovhi$jug$1@fred.mathworks.com>...
> Dear All,
> I want to color my contour base on value of Z, if Z<=1 the color will be white and if Z>1 the color will be light gray.
> I succeed to plot the contour with the label as command below but still not success to coloring it.
>
> [C,h]=contour(X,Y,Z);
> clabel(C,h,'FontSize',10,'Rotation',0);
> colormap gray
>
> Thanks in advance for help.
>
> Bahari

Re: coloring contour plot

Bahari — Mon, 10 Aug 2009 14:07:03 -0400

Thanks a lot, could you pls give an example to create my own colormap. If I can reverse the colormap gray, I think, a little bit I can solve my problem.

Another things, I found this from matlab Help:
"[C,h,CF] = contourf(...) returns the contour matrix C as calculated by the function contourc and used by clabel, a vector of handles h to patch graphics objects (instead of a contourgroup object, for compatibility with MATLAB Version 6.5 and earlier) and a contour matrix CF for the filled areas."

I think this command can help me to solve my problem but how to use this "[C,h,CF] = contourf(...)" I'm not so understand. Any one can help?

Regards

Bahari

"Lorenzo Guerrasio" <lorenzo.guerrasio@email.it> wrote in message <h5p776$8pl$1@fred.mathworks.com>...
> You could simply create your colormap and than load it everytime you make a figure.
>
> "Bahari " <baid69@yahoo.co.uk> wrote in message <h5ovhi$jug$1@fred.mathworks.com>...
> > Dear All,
> > I want to color my contour base on value of Z, if Z<=1 the color will be white and if Z>1 the color will be light gray.
> > I succeed to plot the contour with the label as command below but still not success to coloring it.
> >
> > [C,h]=contour(X,Y,Z);
> > clabel(C,h,'FontSize',10,'Rotation',0);
> > colormap gray
> >
> > Thanks in advance for help.
> >
> > Bahari

Re: coloring contour plot

Lorenzo Guerrasio — Mon, 10 Aug 2009 14:32:03 -0400

there should be several example in help colormap.

"Bahari " <baid69@yahoo.co.uk> wrote in message <h5p9i7$9gc$1@fred.mathworks.com>...
> Thanks a lot, could you pls give an example to create my own colormap. If I can reverse the colormap gray, I think, a little bit I can solve my problem.
>
> Another things, I found this from matlab Help:
> "[C,h,CF] = contourf(...) returns the contour matrix C as calculated by the function contourc and used by clabel, a vector of handles h to patch graphics objects (instead of a contourgroup object, for compatibility with MATLAB Version 6.5 and earlier) and a contour matrix CF for the filled areas."
>
> I think this command can help me to solve my problem but how to use this "[C,h,CF] = contourf(...)" I'm not so understand. Any one can help?
>
> Regards
>
> Bahari
>
>
> "Lorenzo Guerrasio" <lorenzo.guerrasio@email.it> wrote in message <h5p776$8pl$1@fred.mathworks.com>...
> > You could simply create your colormap and than load it everytime you make a figure.
> >
> > "Bahari " <baid69@yahoo.co.uk> wrote in message <h5ovhi$jug$1@fred.mathworks.com>...
> > > Dear All,
> > > I want to color my contour base on value of Z, if Z<=1 the color will be white and if Z>1 the color will be light gray.
> > > I succeed to plot the contour with the label as command below but still not success to coloring it.
> > >
> > > [C,h]=contour(X,Y,Z);
> > > clabel(C,h,'FontSize',10,'Rotation',0);
> > > colormap gray
> > >
> > > Thanks in advance for help.
> > >
> > > Bahari

Re: coloring contour plot

Bahari — Mon, 10 Aug 2009 21:55:22 -0400

Thanks Lorenzo Guerrasio,

This is my solution for this moment:
[C,h]=contourf(X,Y,Z);
clabel(C,h,'FontSize',20,'Rotation',0);
caxis([0.5 1])
colormap gray

I think this is not a good solution but it work. What I done, after run the program I reverse the colormap manual. So I get what I want.

If anybody now how to reverse the colormap gray, let me know.

Any way, thanks for everybody.

Regards

Bahari

"Lorenzo Guerrasio" <lorenzo.guerrasio@email.it> wrote in message <h5pb13$nnp$1@fred.mathworks.com>...
> there should be several example in help colormap.
>
> "Bahari " <baid69@yahoo.co.uk> wrote in message <h5p9i7$9gc$1@fred.mathworks.com>...
> > Thanks a lot, could you pls give an example to create my own colormap. If I can reverse the colormap gray, I think, a little bit I can solve my problem.
> >
> > Another things, I found this from matlab Help:
> > "[C,h,CF] = contourf(...) returns the contour matrix C as calculated by the function contourc and used by clabel, a vector of handles h to patch graphics objects (instead of a contourgroup object, for compatibility with MATLAB Version 6.5 and earlier) and a contour matrix CF for the filled areas."
> >
> > I think this command can help me to solve my problem but how to use this "[C,h,CF] = contourf(...)" I'm not so understand. Any one can help?
> >
> > Regards
> >
> > Bahari
> >
> >
> > "Lorenzo Guerrasio" <lorenzo.guerrasio@email.it> wrote in message <h5p776$8pl$1@fred.mathworks.com>...
> > > You could simply create your colormap and than load it everytime you make a figure.
> > >
> > > "Bahari " <baid69@yahoo.co.uk> wrote in message <h5ovhi$jug$1@fred.mathworks.com>...
> > > > Dear All,
> > > > I want to color my contour base on value of Z, if Z<=1 the color will be white and if Z>1 the color will be light gray.
> > > > I succeed to plot the contour with the label as command below but still not success to coloring it.
> > > >
> > > > [C,h]=contour(X,Y,Z);
> > > > clabel(C,h,'FontSize',10,'Rotation',0);
> > > > colormap gray
> > > >
> > > > Thanks in advance for help.
> > > >
> > > > Bahari