How do I separate negative datas with their row?

First 2 rows contain the long/lat;third row contains the land/water values. I want to separate the files into land and water xyz files for bathymetry use therfore I need the negative values from the 3rd column and their respective rows. I would like to extract the whole row of data containing negative numbers in any of the columns. It has 9135x3 cells of data. Any idea how to do this?

Answer 1

[KSSV]

Let H be your third column.

idx = H<0 ;  % get all negative values logical indices
lon1 = lon(idx) ; 
lat1 = lat(idx) ; 
H1 = H(idx) ; 

If A is your data of size 9135x3.

iwant = A(A(:,3)<0,:) ; 

[Gary Ong]

I am new to matlab so please pardon me.

I am getting this error,

Undefined operator '<' for input arguments of type 'table'.

[KSSV]

Show us the whole code which gave you error.

[Gary Ong]

idx = SG1<0 ;
lon1 = lon(idx) ;
lat1 = lat(idx) ;
h1 = h(idx) ;

Results = SG1(SG1(:,3)<0,:);

this is what I have right now

[KSSV]

How you got SG1, lon, lat; thios is what matters for the error.

[Gary Ong]

H = SG1(:,3); % Land/Water Values
J = SG1(:,1); % Longitude
K = SG1(:,2); % Latitude
idx = H<0 ;  <===Undefined operator '<' for input arguments of type 'table'.
lon1 = J(idx) ;
lat1 = K(idx) ;
h1 = H(idx) ;

Results = SG1(SG1(:,3)<0,:);

I am not sure if I am doing this right. Please guide me.

SG1 is my 9135x3 data which I imported as table. Do I need to convert it to an array?

[KSSV]

H = SG1.(3); % Land/Water Values
J = SG1.(1); % Longitude
K = SG1.(2); % Latitude
idx = H<0 ; 
lon1 = J(idx) ;
lat1 = K(idx) ;
h1 = H(idx) ;

[Gary Ong]

It worked! Thank you for your patience and guidance! @KSSV