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

govindas at msu.edu govindas at msu.edu
Mon Oct 11 17:51:49 EDT 2010



 thank you for the script and I shall try it out! 

Thanks,
Mahalakshmi Quoting SRAVANI A <srisravani.a at gmail.com>:

> 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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>> gradsusr at gradsusr.org
>> http://gradsusr.org/mailman/listinfo/gradsusr
>>
>> 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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