Re: Map data from one type of time axis to another

[Ansley Manke <ansley.b.manke@xxxxxxxx>]

Hi all
Zhen reported back to me that the data is not changed after all when he 
uses var[gt=tnew@ASN] to regrid to a new  time axis.  The @ASN 
transformation does not take the units or origin of the data into 
account, but blindly maps the data onto the new axis.

One can also redefine the axis after opening the file.  Ferret gives a 
warning message.

  yes? use mydata.nc
  yes? let t1 = 1
  yes? let t2 = `var,return=lend`
   !-> DEFINE VARIABLE t2 = 366
 
  yes? def axis/t=`t1`:`T2`:1 TIME
   !-> def axis/t=1:366:1 TIME
  Replacing definition of axis TIME
   *** NOTE: grid  used by data set mydata.nc
   *** NOTE: Redefinition may alter apparent contents of data set
 

zhen.li@gsfc.nasa.gov wrote:

> Hi Ferret users:
>
> My data file is the daily uflx from NOAA/CDC, i.e, 
> "uflx.sfc.gauss.1964.nc". The time axis is
> such that "hours since 1-1-1 00:00:0.0"  with the starting time at 
> 17207328 hr and ending time
> at 17216088hr. I'd like my time axis to be simply the days i,e, from 1 
> to 366 (otherwise the MOM4
> code doesn't take it). I know that I can define a new axis and map the 
> data to new axis
> ( i.e, define axis /t=1:366:1 time1; let new_uflx=uflx[gt=time1@ASN] 
> ), but after I look at the new_uflx
> data, it's no longer the same as the uflx towards the end of the data 
> record.
>
> I wonder how can you map the data from one type of time axis to 
> another with different units?
>
> Thanks,
>
> Zhen