How can i work with a matrix that present floating points

I'm working with bathymetry data and I need to plot with the 'contour' command only the isolate of -1000. However when I try to find this data in my matrix with the command 'find' the answer I get is: 0x1 empty double column vector. In other words, this number is not being treated with an integer. So I can't work with it with practically no contour commands, like 'levels'. But other values ​​in the matrix are being treated as integers. How can I normalize my data to work with it?

%The code im using
figure
[x,y]=meshgrid(lon_batN,lat_batN,bat_N);
contour(x,y,bat_N,[-1000],'ShowText','on')

Answer 1

[Jon]

I don't think the problem is float versus integer. MATLAB is very forgiving on this. Are you sure that your bat_N values are negative and not positive, ie. 1000 m depth is a positive 1000;

By the way you don't need the square brackets around the -1000 in your argument to contour

Answer 2

[Star Strider]

If you want the (x,y) data for that contour, you need to ask contour to give it to you:

c1000 = contour(x,y,bat_N,[-1000],'ShowText','on');

See the documentation for M (contour matrix) under Output Arguments. Note that the actual data begin in the second column of that matrix.