Hi Sudheer ,
You're right that the context [L=6:127] is applied to the filtered data
when you specify it in the FFTA call. Writing out the intermediate
result is always one solution, and can often be a quick and easy way to
get around this kind of thing.
Another way would be to define a new time axis with just the points
that are valid in the filtered variable
let nogap = compressl(nts)
let L1 = t[gt=nts,L=6]
let L2 = t[gt=nts,L=127]
define
axis/t=`L1`:`L2`/units="`nts,return=tunits`"/npoints=`(127-6+1)`/t0="`nts,return=t0`"
tshort
!-> define
axis/t=21250.5:109641/units="hour"/npoints=122/t0="14-JAN-1980
14:00:00" tshort
plot ffta(nts_for_ffta)
To make a really general script, you could use transformations to
define the first and last index to use, instead of 6 and 127, so that
it'd work for other data.
Sudheer Joseph wrote:
Dear Users,
I wanted to do the below steps in ferret but as the ffta gives out an
error though I specify only portion of the time axis where there is
data after the removal during filtration, May this be due to the fact
that the computation for filter and ffta are taking place
simultaniously and there fore the end points available to ffta do not
have datat there?
is there a way to do this computation other than listing the results to
a file and reading that again to a new time axis?
use monthly_navy_winds
let aa = uwnd[i=50,j=20]
let az = aa - aa[t=@ave]
plot az
plot/over lanczos(az, 0.05, 0.1, 11)
plot/over lanczos(az, 0.1, 0.2, 11)
let nts=lanczos(az, 0.1, 0.2, 11)
% both ends of the timeseries are lost due to filter.
plot ffta(nts[l=6:127])
Bailing out of external function "ffta":
FFTA encountered missing data at (i,j,k,l) 50 20 -999 1
**ERROR: error in external function
plot ffta(nts[l=6:127])
--
with best regards
Sudheer
**********************************************************************************
Sudheer Joseph
Scientist
Indian National Centre for Ocean Information Services (INCOIS)
Ocean Valley, Post Box No# 21,
IDA Jeedimetla P.O.
Hyderabad, Ranga Reddy District - 500 055
Andhra Pradesh, India.
TEl:+91-40-23044600(R),Tel:+91-9440832534(Mobile)
Tel:+91-40-23886047(O),Fax:+91-40-23892910(O)
E-mail:sjo@xxxxxxxxxxxxxx;
sudheer.joseph@xxxxxxxxx;
sjo@xxxxxxxxxxxxx.
Web- http://oppamthadathil.tripod.com
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