Averaging every n step column and m step row

Hi, Please help me to resolve the problem I have matrix 3D 8x84 below

X is time (January 2004 - January 2012)

Y is longitude

Z is Value

X = [01-2004 01-2004 01-2004 01-2004 01-2004 01-2004 01-2004 01-2004

    02-2004 02-2004 02-2004 02-2004 02-2004 02-2004 02-2004 02-2004

       :        :       :      :        :       :      :        :

    12-2011 12-2012 12-2012 12-2012 12-2012 12-2012 12-2012 12-2012]

Y = [40 50 60 70 80 90 100 110

     40 50 60 70 80 90 100 110

      :  :  :  :  :  :  :   : 

     40 50 60 70 80 90 100 110]

Z = [23 35 63 45 23 34 55 32

    14 23 34 43 18 26 44 22

     :  :  :  :  :  :  :  :

    21 43 65 22 86 43 66 33]

I want to averaging this matrix every month in every longitude. This would averaging Value at row 1,13,25,37,49,61,73, on longitude(1,1) So I have 3D matrix 8 x 12 (8 point longitude and 12 point monthly) Anyone can help?

Answer 1

[m0xty Wilopo]

Thank you Andrei, this is the fastest way to solve my inquiry

Very happy! Cheers

[Jan]

Please accept the answer, which has solved you question. Comments to answers are wanted in the comment section, not as additional answer. Thanks.

Answer 2

[Andrei Bobrov]

Z = randi([14 66],108,8); % eg

mns = ndgrid(1:12,2004:2012);
[ln,ln] = ndgrid(1:numel(mns),1:8);
Zout=accumarray([repmat(mns(:),size(ln,2),1),ln(:)],Z(:),[],@mean);

[m0xty Wilopo]

This is accepted answer