Hi Deni,
You can shift the time of the event mask using the L=@SHF:n transformation. This just moves the values forward or backward in time. In your case
let/title="12 months before the evant" event_12 = event[L=@shf:12]
In your specific example it will move the first event off the time axis so you may have to make an extended time axis with nothing but missing values if you need that first event.
Cheers,Russ
On 6/1/19 12:24 pm, Deni Okta Lestari wrote:
Dear ferret users,
I am trying to masking index for 12 months before the event. I can't find any command in the official of ferret because it's unavailable. So, what is the command to issue this masking?
yes? list index, event
TIME: 01-JAN-1982 00:00 to 01-JAN-2018 00:00
LONGITUDE: 150W to 90W
LATITUDE: 5S to 5N
Column 1: INDEX
Column 2: EVENT
INDEX EVENT
01-JAN-1982 00 / 1: -0.900 ....
01-FEB-1982 00 / 2: -1.135 ....
01-MAR-1982 00 / 3: -0.118 ....
01-APR-1982 00 / 4: 1.238 ....
01-MAY-1982 00 / 5: 2.153 ....
01-JUN-1982 00 / 6: 2.450 ....
01-JUL-1982 00 / 7: 1.498 ....
01-AUG-1982 00 / 8: 1.263 ....
01-SEP-1982 00 / 9: 1.542 ....
01-OCT-1982 00 / 10: 1.944 ....
01-NOV-1982 00 / 11: 2.732 ....
01-DEC-1982 00 / 12: 2.692 1.000
01-JAN-1983 00 / 13: 2.142 ....
01-FEB-1983 00 / 14: 1.404 ....
01-MAR-1983 00 / 15: 2.001 ....
01-APR-1983 00 / 16: 2.676 ....
01-MAY-1983 00 / 17: 3.337 ....
01-JUN-1983 00 / 18: 3.136 ....
01-JUL-1983 00 / 19: 1.677 ....
01-AUG-1983 00 / 20: 0.984 ....
01-SEP-1983 00 / 21: 0.260 ....
01-OCT-1983 00 / 22: -0.554 ....
01-NOV-1983 00 / 23: -0.717 ....
01-DEC-1983 00 / 24: -1.264 ....
Best regards,
Deni
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Program Pascasarjana Universitas SriwijayaDeni Okta LestariIlmu Lingkungan
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