Selecting pixels within a matrix

Suppose I have a matrix of land heights which range from 0-5000m.

How can i create a new matrix of the same size, that keeps only the values between 300-400, and sets all the rest to 0.

eg. Orignial matrix (completely hypothetical) = [0 100 300 800 5000; 200 400 600 1000 2000; 400 3000 4000 4000 5000; etc etc] New Matrix = [0 0 300 0 0; 0 400 0 0 0;400 0 0 0 0; etc ]

So far i have this: [m,n] = size(Land) for i = 1:m for j = 1:n if 300<Land(i,j)<400 matrix(i,j) = Land(i,j) else matrix(i,j) = 0 end end end

However this isnt even close to being right! Please help!Thank you!

[philippa]

sorry my original code didnt come out right... it looks like this:

[m,n] = size(Land)

for i = 1:m

for j = 1:n

if 300<Land(i,j)<400

matrix(i,j) = Land(i,j)

else

matrix(i,j) = 0

end

end

end

Answer 1

[Fangjun Jiang]

A=[0 100 300 800 5000; 200 400 600 1000 2000; 400 3000 4000 4000 5000] 
A(A<=300)=0;
A(A>=400)=0;