How to plot a map over plotm

Hi, I have a 360*720 matric which includes the value of the temperature of the globe with the spatial resolution of 0.5 degree. I would like to plot this metric as a map after I used the following code; figure;

worldmap world

load coastlines

plotm(coastlat, coastlon)

Thanks in advace.

[Sreeraj T]

I am not sure whether you are following this thread anymore. I do not see any MWE. But I guess that instead of 'plotm', the command 'surfm' would be useful.