function y = global_avg(x,gw,landfrac)

[im jm]=size(x);

y = zeros(3,1);


area2 = 0;
area3 = 0;

for i=1:im
for j=1:jm
    y(1,1) = y(1,1)+gw(j)*x(i,j)/2/im;

    if(landfrac(i,j)>.95)
     area2 = area2+gw(j);
     y(2,1) = y(2,1)+gw(j)*x(i,j);
    else
     area3 = area3+gw(j);
     y(3,1) = y(3,1)+gw(j)*x(i,j);
   end
end
end

y(2,1) = y(2,1)/area2;
y(3,1) = y(3,1)/area3;