Shaded Contour and Line Contour in one CONTOURF

I have a matrix A=m x n; X=m x 1; Y=n x 1; contourf(X,Y,A','linestyle','none')

I wish to superpose another matrix B (m*n) "in LINE CONTOUR" onto the previous

Please help...

It would be great if I knew to plot matrix B both in single color line with values written in between, or a contour with different color scheme....

[jonas]

I don't understand what you mean, what is a line contour? One without faces, like the normal contour?

[Bhowmik.U]

Please find the enclosed image as an example image I just downloaded from Internet to make my problem clear

Here the color is my Matrix : A (in shaded form) and by line contour, I mean the black lines within it, with lables in number.. (my Matrix B)

...Hope I am clear now

Answer 1

[jonas]

Yea that's fairly easy. An example:

A=peaks(100);
B=peaks(75);
[~,h1]=contourf(A,'linestyle','none');hold on
[c,h2]=contour(B,'linecolor',[0 0 0])
set(h2,'ContourZLevel',10)
clabel(c,h2)

The second to last row makes sure that h2 is always drawn on top, although this case its not needed.

[Bhowmik.U]

Sir, the problem here is that it overrides the color scale of h1

secondlt how do I plot only certain levels of B on top of contour plot of A

[jonas]

What do you mean it overrides the color scale of h1? The contour h2 shows no color, although its colormap is the same as h1. If you want two different colormaps, then that's an easy fix. However, please clarify what you mean.

The second problem is easy, just specify the contourlines as input. For example, say you want to plot lines at Z=[1 5 10]:

[c,h2]=contour(B,'linecolor',[0 0 0],'levellist',[1 5 10])

[jonas]

Okay, I think I understand what you mean. You probably want the colorscale of the first plot to be completely unlinked to the colorscale of the second, so that they do not influence eachother in any way. This can be done by plotting them on different axes. Try this example:

%%Create and link two axes
ax1=axes
ax2=axes
linkaxes([ax1 ax2],'xy')

%%Some data
A=peaks(100);
B=peaks(75);

%%Toggle first axes and plot contour with facecolor
axes(ax1);hold on
[~,h1]=contourf(A,'linestyle','none');hold on
%colorbar(ax1)

%%Toggle second axes and plot contour lines
axes(ax2)
[c,h2]=contour(B.*100,'linecolor',[0 0 0],'facecolor','none')

%%Put second plot on top
set(h2,'ContourZLevel',10)

%%Add labels
clabel(c,h2)

%%some settings
set([ax1 ax2],'xlim',[0 100],'ylim',[0 100],'color','none')

Is this what you mean?

[Bhowmik.U]

Thanks a trillion Sir for all your help!..it worked like cream!

[Bhowmik.U]

however can you please suggest at which place I should use colorbar option

[Bhowmik.U]

because when I try inserting colorbar after

%colorbar(ax1)

the colorbar enters the plot area producing mess.. :(

[jonas]

Happy to help.

The problem is that the colorbar changes the position-property of one axes when you place it outside of the plot area, as it is set to location='eastoutside' by default. There are several ways to solve this:

1) Align the position of the two axes at the end of the script. Add this at the end of the script:

cb=colorbar(ax1)
ax1pos=get(ax1,'position')
set(ax2,'position',ax1pos)

2) add colorbar inside the plot and then move it outside by changing its position. This prevents the axes position from being changed at all. Add this at the end of the script:

cb=colorbar(ax1,'location','west')
cb.Position=cb.Position+[0.6 0 0 0];

3) add colorbar normally, i.e. outside of plot, and change the position of the axes back again afterwards

ax1pos=get(ax1,'position')
cb=colorbar(ax1)
set(ax1,'position',ax1pos)