Using discretize to reduce the size of a matrix

I have a large matrix that I need to represent visually. Contourf is perfect for what I need to do but the problem is that for matrices above a certain size, contourf takes an extremely long time work. I was wondering is there a way to half the size of a matrix using the discretize command? Looking at the mathworks page for discretize, the instructions are somewhat confusing and the apparent need to specify edges seems like a possible problem. I was thinking of binning each row in half and each column in half by combining every even numbered data point with the adjacent odd numbered data point. Is this possible with discretize or must each edge be specified?

Answer 1

[KSSV]

You donwsample your matrix by some step. Lat A be your matrix.

skip = 2 ;   % skip these many number rows and columns, change it accordingly
A_reduced = A(1:skip:end,1:skp:end) ;  % matrix reduced, now use contourf

[Aaron Smith]

Thanks, that works great.