Hi,One thing you can do is that you can extract the dataRepeat/l=26:1073:1 (save/append/file=file.nc var)On Jan 24, 2018 7:14 PM, "USHNANSHU DUTTA" <ushnanshudutta@xxxxxxxxx> wrote:Hello, ferreters,I have a data which timestep is from 1 to 1073. but the first 25 timesteps has no value. while using FFTA the error is coming saying missing data at L=1.I have used redefining axis command but it is in vain. Can you please help me to arrange the data such a way it will trim the first 25 timesteps and will start from 1 at 26th timestep.On Wed, Jan 24, 2018 at 1:02 PM, USHN--