Thread Subject: colorbar problem

hello,

i have 2 matrices A and B. A contains n unique values and
B contains m<n values (a subset of n)

i want to plot both matrices using the same colors and a
common colorbar
to keep things easy i created another matrix C=[A B]
and i do:

figure
imagesc(C);
n=length(unique(C));
colormap(jet(n))
colorbar('YTick',1:n,'YTickLabel',unique(C))

but it does not work... i see that the same color is used
for two different values and the colorbar has all the
elements grouped down and not nicely distributed along the
bar.

any suggestions on how to improve this "poor" script?

Thanks in advance!!

"carmelo ":
<SNIP colorbar-tick headache...

one of the solutions

% the data
     a=magic(5);
     b=fix(a/2)-1;
     c=[a,b];
% the engine
     cu=unique(c);
     n=numel(cu);
     imagesc(c);
     colormap(jet(n));
     ch=colorbar;
     yl=get(ch,'ylim');
     ys=diff(yl)/n;
     yt=linspace(yl(1)+ys,yl(2),n)-.5*ys;
% - the colorbar
     set(ch,'ytick',yt,'yticklabel',cu);

us

"us " <us@neurol.unizh.ch> wrote in message <fqp3t6
$aae$1@fred.mathworks.com>...
> "carmelo ":
> <SNIP colorbar-tick headache...
>
> one of the solutions
>
> % the data
> a=magic(5);
> b=fix(a/2)-1;
> c=[a,b];
> % the engine
> cu=unique(c);
> n=numel(cu);
> imagesc(c);
> colormap(jet(n));
> ch=colorbar;
> yl=get(ch,'ylim');
> ys=diff(yl)/n;
> yt=linspace(yl(1)+ys,yl(2),n)-.5*ys;
> % - the colorbar
> set(ch,'ytick',yt,'yticklabel',cu);
>
> us

Thanks us!!

"carmelo " <km.nospam.scriba.nospam@yahoo.esnospam> wrote
in message <fqp846$a3c$1@fred.mathworks.com>...
> "us " <us@neurol.unizh.ch> wrote in message <fqp3t6
> $aae$1@fred.mathworks.com>...
> > "carmelo ":
> > <SNIP colorbar-tick headache...
> >
> > one of the solutions
> >
> > % the data
> > a=magic(5);
> > b=fix(a/2)-1;
> > c=[a,b];
> > % the engine
> > cu=unique(c);
> > n=numel(cu);
> > imagesc(c);
> > colormap(jet(n));
> > ch=colorbar;
> > yl=get(ch,'ylim');
> > ys=diff(yl)/n;
> > yt=linspace(yl(1)+ys,yl(2),n)-.5*ys;
> > % - the colorbar
> > set(ch,'ytick',yt,'yticklabel',cu);
> >
> > us
>
> Thanks us!!
>

oops! it seems that it does not work like i wanted it to
work. i have 6 unique elements in c but when i do:
imagesc(c);
colormap(jet(n));
the same color is assigned to two different values in c
and the colorbar is not correct (e.g. value 27 gets yellow
but in the colorbar yellow corresponds to value 35).
am i doing something wrong?

this is c:

c=[
0 0 0 0 27 27 27 0
0 0 0 0 0 0 0
0 0 0 0 27 27 27
0 0 0 0 0 0 0
0
0 0 0 0 27 27 27 27
27 35 0 0 0 0 0
0 0 0 0 27 27 27
27 27 35 0 0 0 0
0
0 0 0 27 25 25 27 27
27 27 35 27 0 0 0
0 0 0 27 25 25 27
27 27 27 35 27 0 0
0
0 0 0 25 25 25 27 27
27 27 27 27 27 25 25
0 0 0 25 25 25 27
27 27 27 27 27 27 25
25
0 0 27 25 25 25 25 27
27 27 27 27 27 27 0
0 0 27 25 25 25 25
27 27 27 27 27 27 27
0
0 0 25 25 25 25 25 25
27 27 27 27 27 27 0
0 0 25 25 25 25 25
25 27 27 27 27 27 27
0
0 0 25 27 27 25 25 25
27 27 27 27 27 33 0
0 0 25 27 27 25 25
25 27 27 27 27 27 27
0
0 25 25 25 27 25 25 25
27 27 27 27 33 0 0
0 25 25 25 27 25 25
25 27 27 27 27 27 0
0
0 27 27 25 25 25 25 27
25 27 27 38 38 0 0
0 27 27 25 25 25 25
27 25 27 27 27 27 0
0
0 25 25 25 25 25 25 27
27 27 27 38 0 0 0
0 25 25 25 25 25 25
27 27 27 27 27 0 0
0
25 25 27 27 27 27 27 27
27 27 27 27 0 0 0
25 25 27 27 27 27 27
27 27 27 27 27 0 0
0
0 0 0 27 27 27 27 27
27 27 27 27 0 0 0
0 0 0 27 27 27 27
27 27 27 27 27 0 0
0
0 0 0 0 0 27 27 27
27 27 27 0 0 0 0
0 0 0 0 0 27 27
27 27 27 27 0 0 0
0
0 0 0 0 0 0 0 0
27 27 27 0 0 0 0
0 0 0 0 0 0 0
0 27 27 27 0 0 0
0
];

"carmelo ":
<SNIP useless amount of data...

do not copy/paste a huge matrix, which - to boot - cannot
be recovered due formatting issues; this is tedious...

create the smallest possible data set that reproduces your
problem...

now, looking at some of the data it seems you have
something like

     c=[0,25:27,33,37,38];

the engine proposed earlier assumes that your <cu> is
continuous!
otherwise, simply adjust the engine as follows

     c=[
          0,25,26,33
          27,0,35,38
     ];
% the engine
     cu=unique(c);
     [cx,cx]=histc(c,cu); % <- add this!
     n=numel(cu);
     imagesc(cx); % <- use this!
     colormap(jet(n));
     ch=colorbar;
     yl=get(ch,'ylim');
     ys=diff(yl)/n;
     yt=linspace(yl(1)+ys,yl(2),n)-.5*ys;
% - the colorbar
     set(ch,'ytick',yt,'yticklabel',cu);

us

"us " <us@neurol.unizh.ch> wrote in message
<fqr3qr$82u$1@fred.mathworks.com>...
> "carmelo ":
> <SNIP useless amount of data...
>
> do not copy/paste a huge matrix, which - to boot -
cannot
> be recovered due formatting issues; this is tedious...
>
> create the smallest possible data set that reproduces
your
> problem...
>
> now, looking at some of the data it seems you have
> something like
>
> c=[0,25:27,33,37,38];
>
> the engine proposed earlier assumes that your <cu> is
> continuous!
> otherwise, simply adjust the engine as follows
>
> c=[
> 0,25,26,33
> 27,0,35,38
> ];
> % the engine
> cu=unique(c);
> [cx,cx]=histc(c,cu); % <- add this!
> n=numel(cu);
> imagesc(cx); % <- use this!
> colormap(jet(n));
> ch=colorbar;
> yl=get(ch,'ylim');
> ys=diff(yl)/n;
> yt=linspace(yl(1)+ys,yl(2),n)-.5*ys;
> % - the colorbar
> set(ch,'ytick',yt,'yticklabel',cu);
>
> us

sorry about posting the original c matrix, i thought that
it could help... I regretted my decision when i saw the re-
formating after posting the message....and, indeed, the
message was that the values are not continous

Thanks, this solves the problem!