Hi Both,
This has already been solved, but dealing with the default abstract
axes is something people do a lot, so I think it's worth adding one more
item. If you do a "LOAD var" to read in the data, then the RETURN
keyword
and other grave-accent expressions will give the correct length:
yes? FILE/VAR="a, b", varfile.dat
yes? LOAD a
yes? LET ndat = `a, RETURN=isize` ! returns the total # of points
Ansley
Jaison Kurian wrote:
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
***************************************
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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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