Creating 2D matrix from the "cut" of a 3D matrix

Question

I have a 3D matrix ch4_global 180 by 360 by 452 (latitude by longitude by time). I want to create a 2D matrix from the cut of the 3D matrix. The cut matrix is a 2D matrix(id) of size 451 by 1. I need to cut ch4_global (180x360) using id for each time.

id=find(Latitude<=-10.5 & Latitude>=-20.5 & Longitude<=-35.5 & Longitude>=-75.5);

So, I want:

co(:,time)=ch4_global(id,time)

Answer 1

Judging by the examples (and array sizes) given in your question, I'm assuming you're working in the [elevation <=> θ <=> latitude, azimuth <=> φ <=> longitude] convention for spherical coordinates:

... and the positions in the array correspond to the appropriate angles in degrees. For this reason I'm thinking you can get what you want by simple indexing of a sub-array:

cut_ch4_global = ch4_global( (-20:-11)+90, (-75:-35)+180, :);

Note that the result is still a 3D array, but now it only contains the lat/lng you're interested in (if my assumptions are correct).

I apologize in advance for any "off-by-1" errors.

Answer 2

squeeze will do the trick for you.

A = rand(180,360,452);
B = squeeze(A(:,:,1));