Is there a contourc equivalent for contourm?

Hello,

I would like to compute contours on geotiffs without producing a plot. For regular rectangluar data 'contour' will compute the contours and plot them, and 'contourc' function will just compute the contours and return the contour matrix without plotting. It appears the geographic contour function 'contourm' works like 'contour' and produces a plot, I would like to get the contours without generating a plot.

Right now my solution is this:

set(0,'DefaultFigureVisible','off');  
altContour = contourm(geoData,geoRef,'LevelList',geoAltitude,'Visible','off');
close(gcf);
set(0,'DefaultFigureVisible','on');

But this is still incurring overhead penalties for setting up the figure... I would ideally like a function like 'contourmc'. Is there some function, even internal or undocumented, that I can use to achieve this?