Re: Grads Binary file

Prince,

Thanks for the information on how you deal with Grads files. We got
some sample data files from a user, and we're going to look into
seeing what kind of direct NCL support we can provide for Grads files.

--Mary

On Sat, 4 Mar 2006, Prince K. Xavier wrote:

>
> I'm a GrADS user too..
>
> During my transition to NCL I too am facing the same problem. What I do is to
> convert the Grads file to NetCDF with the 'lats4d' package in Grads. Then use
> the 'addfile' command to read the netcdf.
>
> Else, to read the binary file of Grads, one has to supply all the attributes
> explicitly to the data read with 'fbindirread'
>
> Please see a NCL script segment.
>
>
> fname = "/user1/prince/Reynolds/1x1/sstan_jan1982_dec2002.grd"
>
> ntim = 252
> nlat = 180
> nlon = 360
>
> lonL = 0
> lonR = 360
> latS = -89.5
> latN = 89.5
>
> years = sprinti("%4i",ispan(1982,2002,1)) ; write integers as
> string
> months = sprinti("%0.2i", ispan(1,12,1)) ; ditto for months
>
> time = new(dimsizes(years)*dimsizes(months),"integer") ; create time
`> array
> k=0
> do i=0,dimsizes(years)-1
> do j = 0, dimsizes(months)-1
> time(k)=stringtointeger(years(i)+months(j)) ; combine to
> strings
> k=k+1 ; and convert
> to int
> end do
> end do
>
>
> lat = fspan(latS,latN,nlat)
> lat_at_units = "degrees_north"
>
>
> lon = fspan(lonL,lonR,nlon)
> lon_at_units = "degrees_east"
>
> sst = fbindirread(fname,0,(/ntim,nlat,nlon/), "float")
>
> sst!0 = "time"
> sst!1 = "lat"
> sst!2 = "lon"
>
> time_at_long_name = "time"
> time_at_units = "yyyymm"
>
> sst&time = time
> sst&lat = lat
> sst&lon = lon
> sst@_FillValue = -32767
>
> ------------------------------------------
>
> Hope this helps!
> Prince
>
> On Fri, 3 Mar 2006, Dennis Shea wrote:
>
>>
>> Well, I am not a GrADS user :-)
>> so I do not know. You may have to go to the GrADS
>> WWW and read about it.
>>
>> GrADS format is basically a flat binary file.
>>
>> I speculate that the following will work.
>>
>> rain = fbindirread("1991new.grads", 0, 365, "float")
>> print(rain)
>>
>> ==========================================================================
>> > On Thu, 2 Mar 2006, sahana_paul wrote:
>>>
>> Hi,
>> I have dat in grads binary file say temp.grads and descripter file
>> temp.ctl and temp.map also. Is it possible to use this file in NCL or
>> anyother
>> way to convert it netcdf, grib, or any other file format.
>>
>>> I have station data, so how to assaign the lat lon to the
>>> perticular station.
>>> my ctl file is,
>>>
>>> dset ^1991new.grads
>>> dtype station
>>> stnmap 1991new.map
>>> undef -9999.00
>>> title rain
>>> tdef 365 linear 01jan1991 1dy
>>> vars 1
>>> rain 0 99 rain
>>> endvars
>>>
>>> in that case I cannot use the grads2nc.
>>>
>>> regards
>>>
>>> sahana
>>>
>>
>> _______________________________________________
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>>
>
> --
> Prince K XAVIER
> Centre for Atmospheric and Oceanic Sciences Indian Institute of Science
> Bangalore - 560 012 INDIA http://caos.iisc.ernet.in/hpg/students/prince.html
> __________________________________________________ Phone No. +91 80 2293 2505
> (Extn:201)
> +91 98808 19172 (Mobile)
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Received on Wed Mar 08 2006 - 16:56:56 MST