Re: Getting number of variables

[Jaison Kurian <jaison@xxxxxxxxxxxxxxxxxx>]

Hi Sudheer,
              It not that diffcult task to know the number of data lines 
in text files, provided your ascii input files have some similarity 
 
        1. either all of them should have same number of header lines
            that we need to skip using /SKIP qualifier.
        2. or none of the file does have any header lines..the data
            values should start from the very first line of the ascii 
            file.

  The total number fo lines you can get onto a variable as follows

        yes? let flines = `{spawn:"cat example.dat | wc -l"}`
         !-> DEFINE VARIABLE flines =      10
        yes?

  suppose you don't have any header lines then

        yes? define axis/x=1:`flines`:1 xfile
        yes? define axis/x=xfile        gfile
        yes? file/grid=gfile/var=var1   example.dat


   Hope this helps

   with regards 

   Jaison 


On Mon, 6 Dec 2004, Sudheer Joseph wrote:

> Dear Jaison,
>                               I agree that it is good to define the axis 
> properly and read the variable in to it , But I am doing a batch job where 
> in, there is a list of data going to ferret and getting data of 
> corresponding locations form a netcdf file and do some calculation involving 
> both. here it is hard to define the axis since it varies its size with every 
> file and it depends on the number of common point s in both datasets.
> 
> thanks,
> Sudheer
> 
> 
> ***************************************
> Dr. Sudheer Joseph
> Indian National Centre for Ocean Information Services
> Gajularamaram B.O., IDA Jeedeemetla S.O.
> Via Pragathi Nagar, Kukatpally, Hyderabad
> Pin:5000 55
> Tel:+91-40-23044600(R)
> Tel:+91-40-9440832534(Mobile)
> Tel:+91-40-25503595(O)
> Fax:+91-40-25503596(O)
> E-mail:sjo@rediffmail.com;
> callsjo@yahoo.com;
> sjo@incois.gov.in.
> Web- http://oppamthadathil.tripod.com
> ***************************************
> 
> 
> 
> >From: Jaison Kurian <jaison@caos.iisc.ernet.in>
> >To: ferret_users@noaa.gov
> >CC: Sudheer Joseph <sjo_cma@hotmail.com>
> >Subject: Re: Getting number of variables
> >Date: Tue, 7 Dec 2004 01:26:15 +0530 (IST)
> >
> >Hi Sudheer,
> >              I always prefer to read the data from ASCII file to a
> >properly defined grid instead of depending on the default way. If
> >you are doing it in this way then you can use the variable just like
> >one in a good NetCDF file. IF you are interested please have a look at
> >Ferret manual : Ch2 Sec5.1.  Reading ASCII files , and
> >Ref Sec4.2.  DEFINE AXIS.
> >
> >  Here is an example. If you have any doubts please let me know.
> >
> >  Hope this helps
> >
> >  With Regards
> >
> >  Jaison
> >
> >!-------------example.dat--------------
> >29.50
> >28.95
> >-999.99
> >27.30
> >28.60
> >29.40
> >-999.99
> >29.50
> >28.60
> >28.30
> >!-----------example.jnl---------------
> >! Let us read the data in example.dat to a proper grid/axis.
> >!   we have 10 data values, so define an axis with 10 points.
> >!   define a grid only with this axis, and read the data onto this
> >!   grid.
> >
> >     DEFINE AXIS/x=1:10:1  xfile
> >     DEFINE GRID/x=xfile   gfile
> >
> >     FILE/grid=gfile/var=var1 num_of_points.dat
> >     set var/bad=-999.99 var1    ! set only the missing value..OR
> >     ! set var/bad=-999.99/title=""Temperature"/units="^oC" var1
> >     list var1
> >
> >     let vardev      = var1 - var1[i=@AVE]
> >     let vardevsq    = vardev^2
> >     let sumsqvardev = vardevsq[i=@sum]
> >
> >! now ..to get the number of valid data points use @NGD..simple one
> >! please note that here `var1,return=isize` - var1[x=@nbd] will also
> >! return accurate value(8).
> >
> >     let good_pts    = var1[i=@NGD]
> >     list good_pts
> >
> >     let myoutput = sumsqvardev/good_pts
> >     list myoutput
> >
> >!-----------------end of example.jnl--------------------------
> >
> >On Mon, 6 Dec 2004, Sudheer Joseph wrote:
> >
> > > Dear Users
> > >                         I would like to get  variance calculted by 
> >defining
> > > file/var=var1  vardat.dat
> > > ! The axis under consideration is irregular
> > > let vardev=var1-var1[x=@ave]
> > > let vardevsq= vardev^2
> > > let sumsqvardev=vardevsq[x=@sum]
> > > and then to devide it by the number of points i wanted to get the actual
> > > number of points
> > > I tried using the `var1,return=size` - var1[x=@nbd] but is not working 
> >since
> > > the size of axis is not limited
> > > it gives a return of 20000+ value which is the default ferret axis size
> > > I would like to get the actual number of variables to devide the sum of
> > > suired deviations.
> > > I realise that there is a function @var existing in ferret but wanted to 
> >use
> > > the manual calculation for some cross checking
> > > can any one help
> > > thanks,
> > > sudheer
> > >
> > >
> > > ***************************************
> > > Dr. Sudheer Joseph
> > > Indian National Centre for Ocean Information Services
> > > Gajularamaram B.O., IDA Jeedeemetla S.O.
> > > Via Pragathi Nagar, Kukatpally, Hyderabad
> > > Pin:5000 55
> > > Tel:+91-40-23044600(R)
> > > Tel:+91-40-9440832534(Mobile)
> > > Tel:+91-40-25503595(O)
> > > Fax:+91-40-25503596(O)
> > > E-mail:sjo@rediffmail.com;
> > > callsjo@yahoo.com;
> > > sjo@incois.gov.in.
> > > Web- http://oppamthadathil.tripod.com
> > > ***************************************
> > >
> > > _________________________________________________________________
> > > All the news that matters. Just the way you like it.
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> > >
> >
> >--
> >___________________________________________________
> >
> >     Jaison Kurian
> >     Centre for Atmospheric and Oceanic Sciences
> >     Indian Institute of Science
> >     B A N G A L O R E   560 012
> >     Ph: +91-80-3942505
> >         +91-80-3600450
> >     Fax:+91-80-3600865
> >___________________________________________________
> >
> 
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-- 
___________________________________________________

    Jaison Kurian                           
    Centre for Atmospheric and Oceanic Sciences
    Indian Institute of Science
    B A N G A L O R E   560 012
    Ph: +91-80-3942505
        +91-80-3600450
    Fax:+91-80-3600865
___________________________________________________