[gradsusr] help with *.grd files (am new to GrADS)!

[SRAVANI A]

On Mon, Oct 11, 2010 at 1:13 AM, <govindas at msu.edu> wrote:

> Hi,
>
> I am new to GrADS and I would like to get some info with my work. I have a
> gridded dataset *.grd, which I want to convert into ASCII file (or someother
> better format) to be able to do some statistical analysis with. here are my
> basic doubts.....
>
> 1. is it possible that statistical analysis can be performed with *.grd
> file themselves?
> 2. I have my other datasets in different formats like netcdf, ASCII - can I
> import such files into GrADS and work on my statistical analyses?
> 3. As I am not familiar with GrADS and its functionalities,  I was planning
> to do my analyses using R, in which case I want my .grd file converted into
> some other "R"-friendly format (I tried using some R packages/functions to
> convert gridded format into ASCII but, it did not work!)
> 4. if possible, can I get some tutorials specific to above mentioned
> issues, and analyses like PCA, Time-Series analysis, lag auto-correlations
> and stuff..! I was going thro' some tutorials where I obtained basic info
> about reading the .ctl file and plotting out the variables (which helped me
> visualize my dataset actually!)
>
> Thanks,
> Mahalakshmi
>
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>
> hi,
 maha lakshmi i am also new  user in this grads but i know some little bit
of information about u had asked 2 nd question yes we import the netcdf
files in to  the grads just i had given ex: below
'reinit'
outfile1='tke2.dat'
'sdfopen uwnd.2010.nc'
'sdfopen vwnd.2010.nc'
*'set lon -180 180'
*'set lat -90 90'
'set lev 850'
tt=121
while(tt<=181)
'set t 'tt
'psi=fish_psi(uwnd,vwnd.2)'
'chi=fish_chi(uwnd,vwnd.2)'
*'F=2*7.292e-5*sin(lat*3.14/180)'
'dp=cdiff(psi,y)'
'dy=cdiff(lat,y)*3.1416/180'
'dp=cdiff(psi,x)'
'dx=cdiff(lon,x)*3.1416/180'
'dc=cdiff(chi,y)'
'dy=cdiff(lat,y)*3.1416/180'
'dc=cdiff(chi,x)'
'dx=cdiff(lon,x)*3.141/180'
'A=(((dp/dx)*(dp/dx))+((dp/dy)*(dp/dy)))/(2))'
'B=(((dc/dx)*(dc/dx))+((dc/dy)*(dc/dy)))/(2))'
'C=((A+B)/1e012)'
'd aave(C,lon=48,lon=72,lat=5,lat=25)'
*'d aave(vint(lev,C,100)/1e03,lon=30,lon=150,lat=-30,lat=40)'
say result
rec1=subwrd(result,4)
rc=write(outfile1,rec1)
tt=tt+1
endwhile
 i will use above the file for yhe calculati ng the energy. here i used a
.nc file is input and .dat file format as output it gives the calculated
values.
and i suggest to u please verify the grads reference card is there i might
so help ful for u
if there is any complications are there above file please mail me
best regards
sravani


-- 
A.Sravani
Research Scholar
Department of Meteorology & Oceanography
Andhra university
Visakhapatnam
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