finding equal (lon,lat) in another matrix of different size

I have 2 matrices:

A = lon, lat, pressure, temperature

B = lon, lat, depth

A size is bigger than B

I am trying to merge the data from A, B to obtain: (lon, lat, pressure, depth, Temperature)

My logic is:

1. Identify values in which latA=latB AND lonA,lonB
2. export both columns : lon, lat
3. add pressure, depth and temperature values to the final matrix

The problem I face is that I want to

treat (lon, lat) as a one single column so that values do not split(?) like a row

and giving the different size in the two matrices, I want to tell matlab to compare one element (Alat1) with all the elements in B-lat column

I found I could use something like this:

lonMatch = ismember(A(:,1), B(:,1));

latMatch = ismember(A(:,2), B(:,2));

latlonMatch = lonMatch & latMatch; %of course the these 3 lines can be put into 1

Final matrix = A(latlonMatch, 3:end);

I am new to this kind of problem and I do not know how to approach it :(

Answer 1

[Johan]

I'm not sure exactly what you mean by A is bigger than B, if you can give a simple example of A and B it would help in helping you :).

I have put a small example below with bogus values maybe this will help. All in all I do somehting very similar to what you proposed.

A = [1, 2, 50, 300; 1, 3, 65, 305]

A = 2×4

1 2 50 300 1 3 65 305

B = [1, 2, 150]

B = 1×3

1 2 150

list = and(abs(A(:,1)-B(:,1))<eps,abs(A(:,2)-B(:,2))<eps); % find matching values
C = A; %initiate final matrix
C(:,end+1) = NaN; %create a new column filled with NaN
C(list,end) = B(list,end) %Replace NaN by values of B in matching rows

C = 2×5

1 2 50 300 150 1 3 65 305 NaN

[Geraldine Maria Palacios Torres]

Oh I meant the sizes

A =40000x3

A(ix,:)= [7.7, 78.8, 350; 7.9, 81.3, 201]

B=311000x4

B(ix,:)= [8.2, 79.5, 200, -2.2; 7.9, 78.2, 0, 3.2]

[Johan]

Okay, then I guess the code I put before should work (swap A and B though has B as more row than A). You will not get the data of A that have no match in B though, I don't know if that is an issue. Also there are missing absolute value in the logical check (I edited my previous answer)

list = and(abs(A(:,1)-B(:,1))<eps,abs(A(:,2)-B(:,2))<eps)

[Geraldine Maria Palacios Torres]

Thanks a bunch, Johan :)