Re: ncdigest V1 #766

• To: ncdigest@xxxxxxxxxxxxxxxx, netcdfgroup@xxxxxxxxxxxxxxxx
• Subject: Re: ncdigest V1 #766
• From: Don Hooper <hoop@xxxxxxxxxxxx>
• Date: Tue, 4 May 2004 23:28:37 -0600 (MDT)

Hui Du,

Why you didn't email cdcdata@xxxxxxxx, like the readme says, I don't know.
The data are packed, per Unidata NetCDF convention.  See:
        http://www.cdc.noaa.gov/PublicData/faq.html#2

-Hoop
> From owner-ncdigest@xxxxxxxxxxxxxxxx  Tue May  4 21:42:59 2004
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> From: owner-ncdigest@xxxxxxxxxxxxxxxx (ncdigest)
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> Subject: ncdigest V1 #766
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> 
> ncdigest             Tuesday, May 4 2004             Volume 01 : Number 766
> 
> 
> 
> Today's Topics:
> Problems with reading my data
> 
> ----------------------------------------------------------------------
> 
> Date: Tue, 04 May 2004 14:02:10 -0700
> From: "Hui Du" <netcdf@xxxxxxxxxxx>
> Subject: Problems with reading my data
> 
> >Dear netcdf users:
> >>  I am trying to read data from a netcdf file.  But it turned out crazy
> >>  The following are some of the data I have read
> >>  -1.3207933E+10
> >>  -8.3823027E+09
> >>  -5.4078728E+11
> >>  -1.6477924E+12
> >>  -3.1043398E+17
> >>  -1.3207933E+10
> >>  -1.0523522E+10
> >>  -8.1099614E+11
> >>  -2.6932095E+11
> >>They are completely different from what I expect.  Actually , the Data 
> >>should be the following or something
> >>
> >>-12310, -12320, -12315, -12310, -12310, -12320, -12325, -12340, -123
> >>40,
> >>    -12340, -12345, -12350, -12350, -12354, -12360, -12365, -12370, -123
> >>75,
> >>    -12379, -12395, -12410, -12415, -12420, -12425, -12425, -12420, -124
> >>04,
> >>    -12400, -12395, -12385, -12375,
> >>
> >>When I use the same fortran program to read another different fille, it 
> >>works well. The only modification I made is changing the dimension size
> >>
> >>the following is the fortran program, I think it should be right
> >>********************************************************
> >>        program filter
> >>        parameter   (ndims=4)
> >>        parameter   (nlat=73,nlon=144)
> >>        real         data(nlon,nlat)
> >>        integer      ncid,ncidin,ncidout,iv
> >>        integer      rcode
> >>        integer      start(3), count(3)
> >>        data start/1,1,1/
> >>        data count/nlon,nlat,1/
> >>        character*50 fname
> >>        character*20 file
> >>        include '/opt/netcdf/include/netcdf.inc'
> >>        ncidin  =  ncopn('../obs_cdc_olr.ctrl.nc',ncnowrit,rcode)
> >>        iv=4
> >>        k=1
> >>        call rdncdf2d(ncidin,iv,k,data)
> >>        do i=1,5
> >>         do j=1,5
> >>        write(6,*) data(i,j)
> >>        end do
> >>        end do
> >>        stop
> >>        end
> >>
> >>subroutine rdncdf2d(ncidin,id,itime,data)
> >>        parameter    (nlat=73, nlon=144)
> >>        parameter    (ndims=3)
> >>        integer      rcode
> >>        integer      start(ndims), count(ndims)
> >>        real         data(nlon,nlat)
> >>        character*31 dimname
> >>        data start/1,1,1/
> >>        data count/nlon,nlat,1/
> >>        start(3)=itime
> >>        call ncvgt(ncidin,id,start,count,data,rcode)
> >>        return
> >>        end
> >>***********************************************************
> >>
> >>There are some difference between these two file in that one has scale 
> >>factor and offset, the other does not. The following is the part of the 
> >>head information of the two netcdf files
> >>
> >>for    obs_cdc_olr.ctrl.nc   (for this file where the problem happened)
> >>                short olr(time, lat, lon) ;
> >>                olr:long_name = "Daily OLR" ;
> >>                olr:valid_range = 0.f, 500.f ;
> >>                olr:actual_range = 64.75f, 341.9f ;
> >>                olr:units = "W/m^2" ;
> >>                olr:add_offset = 327.65f ;
> >>                olr:scale_factor = 0.01f ;
> >>                olr:missing_value = 32766s ;
> >>                olr:var_desc = "Outgoing Longwave Radiation\n",
> >>                        "O" ;
> >>                olr:precision = 2s ;
> >>                olr:dataset = "NOAA Interpolated OLR\n",
> >>                        "O" ;
> >>                olr:level_desc = "Other\n",
> >>                        "-" ;
> >>                olr:statistic = "Mean\n",
> >>                        "M" ;
> >>                olr:parent_stat = "Individual Obs\n",
> >>                        "I" ;
> >>
> >>for  mm5_lon180_ncep.ctrl.nc  (for this file it works well)
> >>
> >>      float LWOUTNEW(TDAY, LATITUDE110_28, LONGITUDE17_80) ;
> >>                LWOUTNEW:missing_value = -1.e+34f ;
> >>                LWOUTNEW:_FillValue = -1.e+34f ;
> >>                LWOUTNEW:long_name = "outgoing longwave radiation" ;
> >>                LWOUTNEW:units = "W m^-2" ;
> >>
> >>
> >>Would anyone give me some hint about this problem?
> >>Thanks a lot in advance !
> >>
> >>Hui Du
> 
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> End of ncdigest V1 #766
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