overlay with a mask image

Hello, I have the following code which shows an image called "zero", I would like just to overlay a mask image (only 0 and 1 values) of the same dimensions so that 0 values are transparent (and then we can see the values of the "zero" image) and 1 values are shown in black. I would like to do this by changing the code already written the less possible. What could I do? Thank you for your help

hFig = figure(1);

set(hFig, 'Position', [11 11 27 7.5]);

set( gca, 'Units', 'normalized', 'Position', [0.05 0.05 0.93 1.2] );

set(0,'defaultFigureUnits','centimeters');

m_proj('equidistant cylindrical','longitudes',[-15 21],'latitudes',[11.5 18]);

m_gridF('ytick',4,'tickdir','out','ticklen',0.005,'linestyle','none');

hold; Plat=18-[0:13]*0.5;

Plon=-15+[0:72]*0.5;

[Plg,Plt]=meshgrid(Plon,Plat);

m_pcolor(Plg,Plt,zero);shading flat;

hold on;

polarmap(flipud(polarmap),0)

M=m_shaperead('clip');

for k=1:length(M.ncst),

m_line(M.ncst{k}(:,1),M.ncst{k}(:,2),'color','k');

end;

hold;

h=colorbar('SouthOutside');

set(h, 'Position', [0.13 .1 .78 .05]);

set(get(h,'title'),'string','test','fontsize',14)

hold;

Answer 1

[Image Analyst]

See Steve's blog: http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/

[Image Analyst]

Jose's "Answer" moved here:

Thank you for your answer. The link you sent me seems to be broken. I have already researched for solutions in internent but I have not found any solution using a similar code. It is maybe a problem difficult to solve using the m_pcolor function of the m_map package.

[Image Analyst]

Seems like a temporary glitch in their web site. It should be working now. You can also look at Brett's version: http://www.mathworks.com/matlabcentral/fileexchange/22108-showmaskasoverlay