Separating an array into multiple, unequal sized arrays using a limiter

I have a file containing lat/lon coordinates and am trying to separate this large array (>70000 lines) into separate arrays each of less than 1500 lines per. However, if I find a "NaN" values within this array, it has to use this as its limiting agent rather than the 1500 lines.

Eg. If NaN occurs before 1500 lines are read, separate by (1:NaN)x2. If no NaN is read within 1500 values, separate the file in 1500x2.

Example of my array:

46.877355, 303.534205

46.799428, 303.237852

46.690925, 303.632512

46.614782, 303.645623

NaN, NaN

46.494857, 303.361513

46.418715, 303.563425

NaN, NaN

46.361608, 303.764633

46.287368, 303.635356

46.249297, 303.245622

46.237876, 303.876536

Im looking for some help on the code to complete this, so that in the end (for the example file), it would have one array that is 4x2, the next would be 2x2 and the last would be 4x2.

This is what I have so far.

poly01 = [lat(1:index_nan(1)-1),lon((1:index_nan(1)-1))];
k = 1;

for s = 1:1500:length(poly01(:,1));
    if s+1500-1 > length(poly01(:,1));
        seg_poly{k} = poly01(s:end,:);
    else
        seg_poly{k} = poly01(s:s+1500-1,:);
    end;
    k=k+1;
end;

Once the code

poly01 = [lat(1:index_nan(1)-1),lon((1:index_nan(1)-1))];

hits a NaN however, it stops writing and only prints the first 4 lines of the above array.

Thank you in advance, Shannon

Answer 1

[Sean de Wolski]

There's a nice function polysplit that will split this into cells like you want around nans:

x = your_array
cx = polysplit(x(:,1),x(:,2))

 cx = 
    [4x1 double]
    [2x1 double]
    [4x1 double]

After this could go through and further split any cell with more than 1500 rows.