imagesc color map for gridded value

Hi all,

I have a set of three variables of a big data set in a given grid (see below) and I would like to plot Z variables as color scale using imagesc. Could you help me how I can plot?

X = 1:01:5

Y =5:01:8

Z = 1,5,0,10,......

length(X)=length(Y)=length(Z).