Data gap finding in a time series

Hello,

The attached file has two columns, time and levels. It has 6 missing data gaps. I want to find the index of each gap like this;

gap1 index 7-13

gap2 index 38-42

gap3 index 67-81

gap4 index 108-111

gap5 index 141-151

gap6 index 182-184

Your help is highly appreciated.

Thank you

Dash

Answer 1

[Adam Danz]

Compute start and stop indices for NaN segments in height variable (column vector).

nanStartIdx = find(diff(isnan([0;height;0]))==1);
nanStopIdx = find(diff(isnan([0;height;0]))==-1);

Show the results.

% Show index of NaN values
ax = cla(); 
plot(isnan(height), '-k', 'LineWidth', 2)
ylim([-.2, 1.5])
xlabel('index')
ylabel('is NaN')
set(ax, 'YTick', [0,1], 'YTickLabel', {'False', 'True'})
hold on
arrayfun(@(start)xline(start, 'b-','Start'), nanStartIdx)
arrayfun(@(stop)xline(stop, 'c-','Stop'), nanStopIdx)

[Binu]

Thanks Adam. Much appreciated

[Maria Battle]

Good solution! If you wanted Stop to be aligned with the last NaN value of each gap, try

nanStopIdx = find(diff(isnan([0;height;0]))==-1)-1;