Add axes label to pcolor image

Question

I created a pcolor image with each grid shaded in based on a value in the matrix C .

h1 = pcolor(C);
colormap(jet)
h = colorbar;
ylabel(h,'Monthly Correlation (r-value)');
shading flat

Each grid corresponds to a particular year on the x axes and a particular site name on the y axes. How can I add an axes label to show this?

I tried the following but it didn't do anything. Plus, I'd like to put the label in the middle of each grid, not on the edges.

set(h1,'XTick',years')
set(h1,'YTick',a)

x axes labels: years' looks like this (size 15x1 double)

    1999
    2000
    2001
    2002
    2003
    2004
    2005
    2006
    2007
    2008
    2009
    2010
    2011
    2012
    2013

y axes labels: a looks like this (12x1 cell):

'09-003-1003-88101'
'09-009-0027-88101'
'25-013-0008-88101'
'25-025-0042-88101'
'33-005-0007-88101'
'33-009-0010-88101'
'33-011-5001-88101'
'33-015-0014-88101'
'33-015-0018-88101'
'44-003-0002-88101'
'44-007-1010-88101'
'44-009-0007-88101'

Current image looks like this:

Answer 1

You are using the wrong handle. For setting labels you need the axes handle and not the pcolor -handle:

%// get axes handle
ax = gca;
...
%// set labels
set(ax,'XTickLabel',years')
set(ax,'YTickLabel',a)

---

Example:

%// example data
C =  [...
0.06    -0.22   -0.10   0.68    NaN     -0.33;
0.04    -0.07   0.12    0.23    NaN     -0.47;
NaN     NaN     NaN     NaN     NaN     0.28;
0.37    0.36    0.14    0.58    -0.14   -0.15;
NaN     0.11    0.24    0.71    -0.13   NaN;
0.57    0.53    0.41    0.65    -0.43   0.03 ];

%// original plot
h1 = pcolor(C);
colormap(jet)
h = colorbar;
ylabel(h,'Monthly Correlation (r-value)');
shading flat

%// get axes handle
ax = gca;

%// labels (shortened to fit data)
years = [1999, 2000, 2001, 2002, 2003, 2004];
a = {'09-003-1003-88101', '09-009-0027-88101', '25-013-0008-88101',  ...
     '25-025-0042-88101', '33-005-0007-88101', '33-009-0010-88101'};

%// adjust position of ticks
set(ax,'XTick', (1:size(C,2))+0.5 )
set(ax,'YTick', (1:size(C,1))+0.5 )
%// set labels
set(ax,'XTickLabel',years')
set(ax,'YTickLabel',a)