Using Windows Version to Read NDFD NetCDF
Ken Waters
Ken.Waters at NOAA.GOV
Mon Nov 14 19:51:38 EST 2005
Thanks Jennifer. Well then, that certainly explains the problems I was
having. I hope somebody can post 1.9b4 Windows binaries. At this point
I can not use a Linux server for this project so I'm stuck trying to do
it in Windows.
Ken
Jennifer Adams wrote:
> Ken,
> The 'dtype netcdf' option is not available with version 1.8. In order
> to read your netcdf file (which has data projected onto a lambert
> grid), you will definitely need 1.9b4. Unfortunately, this is not
> available for windows.
> Jennifer
>
> On Nov 14, 2005, at 1:57 PM, Ken Waters wrote:
>
>> All,
>>
>> I'm just getting started trying to use GrADS to read netCDF files (the
>> NWS National Digital Forecast Database) on a Windows XP box. The data
>> set has been converted from GRIB2 to CF-compliant netCDF files using
>> the
>> NWS MDL "degrib.exe" utililty
>> (http://www.nws.noaa.gov/mdl/NDFD_GRIB2Decoder/download.php).
>>
>> I've successfully installed the latest Windows build that's available,
>> Ver. 1.8sl11, native windows version. Someone told me that I can use
>> 1.9b4 to read these data, however there are no Windows binaries
>> available for that version on the GrADS website. Is the 1.8sl11
>> version
>> able to read netCDF?
>>
>> I'm having mixed results finding help in the documentation. For
>> example, I found a link labeled "Using GrADS on a PC" (link:
>> http://gmao.gsfc.nasa.gov/software/grads/win32/latest/) and it was a
>> dead link.
>>
>> Has anyone had any success viewing netCDF files using the Windows
>> version? I did as someone suggested and started with the WRF example
>> (http://grads.iges.org/grads/gadoc/wrfvars.ctl) for a control file
>> that's found in the documentation. I did an "ncdump -h" of the netCDF
>> file ("sky.txt", attached) to get the required header information to
>> build the control file and then replaced the information in the WRF
>> example to match my data set as best as I could. However, I seem to
>> not
>> be able to get to step one as I get the following error upon reading
>> the
>> control file ("sky.ctl", attached):
>>
>> ga-> open c:\test\sky.ctl
>> Scanning description file: c:\test\sky.ctl
>> Open Error: Data file type invalid
>> --> The invalid description file record is:
>> --> dtype netcdf
>>
>> The data file was not opened.
>> ga->
>>
>> The "dtype netcdf" line is the exact same line that is in the WRF
>> example control file online. Does this have something to do with the
>> CR/LF problem that someone just posted about? If so, how do I fix it?
>>
>> As you can tell, I'm really pretty lost and not sure if I can even do
>> what I want to do with this version.
>>
>> Thanks much for any help.
>>
>> Ken
>>
>>
>> netcdf sky {
>> dimensions:
>> ProjectionHr = UNLIMITED ; // (174 currently)
>> YCells = 252 ;
>> XCells = 312 ;
>> variables:
>> char MapProjection ;
>> MapProjection:long_name = "MapProjection" ;
>> MapProjection:grid_mapping_name =
>> "lambert_conformal_conic" ;
>> MapProjection:EarthShape = "sphere" ;
>> MapProjection:EarthRadius_KM = 6371.2 ;
>> MapProjection:EarthRadius = "6371.200000 km" ;
>> MapProjection:standard_parallel = 25. ;
>> MapProjection:longitude_of_central_meridian = -95. ;
>> MapProjection:latitude_of_projection_origin = 25. ;
>> MapProjection:LowerLeftLatitude = 29.26025 ;
>> MapProjection:LowerLeftLongitude = -123.12555 ;
>> double YCells(YCells) ;
>> YCells:units = "m" ;
>> YCells:long_name = "y coordinate of projection" ;
>> YCells:standard_name = "projection_y_coordinate" ;
>> YCells:grid_spacing = "5079.406000 m" ;
>> YCells:TrueGridLength_Latitude = 25. ;
>> YCells:_CoordinateAxisType = "GeoY" ;
>> double XCells(XCells) ;
>> XCells:units = "m" ;
>> XCells:long_name = "x coordinate of projection" ;
>> XCells:standard_name = "projection_x_coordinate" ;
>> XCells:grid_spacing = "5079.406000 m" ;
>> XCells:TrueGridLength_Latitude = 25. ;
>> XCells:_CoordinateAxisType = "GeoX" ;
>> float longitude(YCells, XCells) ;
>> longitude:long_name = "longitude coordinate" ;
>> longitude:units = "degrees_east" ;
>> longitude:precision = 6 ;
>> longitude:grid_mapping = "MapProjection" ;
>> longitude:standard_name = "longitude" ;
>> longitude:_CoordinateAxisType = "Lon" ;
>> float latitude(YCells, XCells) ;
>> latitude:long_name = "latitude coordinate" ;
>> latitude:units = "degrees_north" ;
>> latitude:precision = 6 ;
>> latitude:grid_mapping = "MapProjection" ;
>> latitude:standard_name = "latitude" ;
>> latitude:_CoordinateAxisType = "Lat" ;
>> float Sky_SFC(ProjectionHr, YCells, XCells) ;
>> Sky_SFC:long_name = "Total cloud cover" ;
>> Sky_SFC:units = "%" ;
>> Sky_SFC:coordinates = "longitude latitude" ;
>> Sky_SFC:ReferenceTime = 1131642000 ;
>> Sky_SFC:ReferenceTimeString = "2005-11-10 17:00:00
>> 00:00" ;
>> Sky_SFC:gridType = "SCALAR" ;
>> Sky_SFC:level = "SFC" ;
>> Sky_SFC:DescriptiveLevel = "0[-] SFC=\"Ground or water
>> surface\"" ;
>> Sky_SFC:OriginatingCenter = 8, 65535 ;
>> Sky_SFC:precision = 3 ;
>> Sky_SFC:valid_min = 0.f ;
>> Sky_SFC:valid_max = 100.f ;
>> Sky_SFC:NumMissing = 18260 ;
>> Sky_SFC:_FillValue = 9999.f ;
>> Sky_SFC:missing_value = 9999.f ;
>> Sky_SFC:grid_mapping = "MapProjection" ;
>> Sky_SFC:GRIBMessageVersion = 2 ;
>> Sky_SFC:GRIBMessageUnits = "%" ;
>> Sky_SFC:GRIB2_Discipline = 0 ;
>> Sky_SFC:GRIB2_Sect4TemplateNumber = 0 ;
>> Sky_SFC:GRIB2_Sect4ParameterCategory = 6 ;
>> Sky_SFC:GRIB2_Sect4ParameterNumber = 1 ;
>> Sky_SFC:GRIB2_GenerationProcess = 2 ;
>> Sky_SFC:GRIB2_FstFixedSurfaceType = 1 ;
>> Sky_SFC:GRIB2_FstFixedSurfaceValue = 0. ;
>> Sky_SFC:GRIB2_SndFixedSurfaceType = 255 ;
>> Sky_SFC:GRIB2_SndFixedSurfaceValue = 0. ;
>> short ProjectionHr(ProjectionHr) ;
>> ProjectionHr:long_name = "Projection Hour After
>> ReferenceTime" ;
>> ProjectionHr:units = "hours since 2005-11-10 17:00:00
>> 00:00" ;
>> ProjectionHr:_CoordinateAxisType = "Time" ;
>> ProjectionHr:FirstValidTime = 1131645600 ;
>> ProjectionHr:FirstValidTimeString = "2005-11-10
>> 18:00:00 00:00" ;
>> ProjectionHr:FirstProjectionHR = 1. ;
>>
>> // global attributes:
>> :title = "GRIB Data translated to NetCDF" ;
>> :Conventions = "CF-1.0" ;
>> :CreatedBy = "degrib" ;
>> :comment = "Used degrib with: -NetCDF 3" ;
>> :references =
>> "http://www.nws.noaa.gov/mdl/NDFD_GRIB2Decoder/" ;
>> }
>> dset ^sky.nc
>> dtype netcdf
>> undef -888
>> TITLE Sky Cover
>> pdef 252 312 lcc 29.26025 -123.12555 1 1 25.0 -95.0 5079.406 5079.406
>> xdef 270 linear -129 0.1
>> ydef 200 linear 26 0.1
>> zdef 25 linear 1 1
>> tdef 2 linear 11jun2002 3hr
>> vars 1
>> SKY=>Sky_SFC 0 t,y,x Sky Cover
>> endvars
>>
> --
> Jennifer Miletta Adams
> Center for Ocean-Land-Atmosphere Studies (COLA)
> 4041 Powder Mill Road, Suite 302
> Calverton, MD 20705 USA
> jma at cola.iges.org
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