Re: Netcdf files: creation and merge

Louis,

For starters, it's better to have a "time" coordinate array that are numeric values rather than strings (array of characters on a NetCDF file).

If you want a string time array, then the way to do this is have both: a time numeric array, and a "chartime" (or whatever you want to call it) character array.

With that in mind, please see the attached "write_netcdf.ncl" script.

It's set up to read the data off your ASCII files, and then there's a big block of code for defining all the variables, including both the "time" and "chartime" arrays.

I don't know what format you want the "time" array in, so I just made it a double with the value YYYYMMDDHH.minute_fraction.

Note that I used "str_get_cols" to extract pieces of the input file names for the output NetCDF file name.

--Mary

On Nov 23, 2011, at 12:29 AM, louis Vonder wrote:

> Many thanks Mary,
>
> Sorry for few information I given in my last email.
>
> The NCEP/NCAR time that I am talking about look like this 2010:06:01:00:30:00
> (Year=2010, Month=06, Day=01, LST=00:30:00).
>
> Here attached *.txt files that I listed. Each file contain a parameter recorded every 30 min during a day starting at 00:30 LST.
>
> So, i want to generated date from the order of files.
> For example
>
> XCut_025_FLFC_01_213K.txt -> 2010:06:01:00:30:00
> XCut_025_FLFC_02_213K.txt -> 2010:06:01:01:00:00
>
> After this operation the unique file generated should have three dimension (time, lat, lon).
> With these I can manipulate my netcdf data more easily.
>
> I guess that informations I send now can better give you some idea on what I am trying to do?
>
> Regards
>
> Louis
>
>
> --- En date de : Mar 22.11.11, Mary Haley <haley@ucar.edu> a écrit :
>
> De: Mary Haley <haley@ucar.edu>
> Objet: Re: [ncl-talk] Netcdf files: creation and merge
> À: "louis Vonder" <appopson@yahoo.fr>
> Cc: "ncl-talk@ucar.edu forum" <ncl-talk@ucar.edu>
> Date: Mardi 22 novembre 2011, 22h16
>
> Louis,
>
> I need some clarification. Exactly what problem are you having generating the date? You said you want it to look like the one in the NCEP/NCAR dataset. What do these dates look like?
>
> Also I'm not sure what your question is about writing the data to one file. Right now, you have all the NetCDF file stuff inside the loop. If you want to write your data to one file, you'll need to move the file definition code outside the loop, but then add a third dimension along with "lat" and "lon", called something like "date" or "time".
>
> It would help if you can provide the *.txt files that you list below.
>
> --Mary
>
>
> On Nov 22, 2011, at 10:15 AM, louis Vonder wrote:
>
>> Dear all,
>>
>> I have a ncl code (inspired from ncl examples) that I am using to save my data in netcdf format.
>> But this code creates for each ascii file a netcdf data, unfortunately this procedure is not nice !!!
>> Now I want to better customize this script so that i can save all my data in a unique netcdf file.
>>
>> But I am facing a problem to generate the date.
>> For example, my files are named as the following:
>>
>> XCut_025_FLFC_01_213K.txt
>> XCut_025_FLFC_02_213K.txt
>> XCut_025_FLFC_03_213K.txt
>> XCut_025_FLFC_04_213K.txt
>>
>> Where 01, 02, 03, 04 correspond to 00:30 LST, 01:00 LST, 01:30 LST and 02:00 LST (LST = Local Solar Time).
>>
>> The year can be for example 2010 during the month of August.
>>
>> So I want that the generated file contain date such as in netcdf file generated by NCEP/NCAR dataset.
>>
>> Below the script I am using
>>
>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/shea_util.ncl"
>>
>> begin
>>
>>
>>
>> nlat = 58
>> ini_lat = 1.
>> lat = ini_lat + (ispan(0, nlat-1, 1)*0.25)
>>
>>
>> nlon = 66
>> ini_lon = 1.5
>> lon = ini_lon + (ispan(0, nlon-1, 1)*0.25)
>>
>>
>> lat@units = "degrees_north"
>> lat@long_name = "latitude"
>> lon@units = "degrees_east"
>> lon@long_name = "longitude"
>>
>>
>>
>> fili = systemfunc("ls XCut_025_FLFC_*_235K.txt")
>> nfil = dimsizes( fili )
>>
>> do n=0, nfil - 1
>> name = stringtocharacter(fili(n))
>> name1 = name(0:20)
>> name2 = chartostring(name1)
>>
>> dummy_data = asciiread(fili(n), (/nlat, nlon/), "float")
>>
>> ; Set up coordinate arrays so we can overlay on map.
>> dummy_data!0 = "lat"
>> dummy_data!1 = "lon"
>> dummy_data&lat = lat
>> dummy_data&lon = lon
>> dummy_data@units = "%"
>> dummy_data@_FillValue = -9999.
>> dummy_data@missing_value = dummy_data@_FillValue
>> dummy_data@long_name = "Fractional coverage"
>>
>> diro = "./" ; Output directory
>> filo = name2+".nc" ; Output file
>> system("/bin/rm -f " + diro + filo) ; remove if exists
>> fout = addfile (diro + filo, "c") ; open output file
>>
>>
>> ;===================================================================
>> ; explicitly declare file definition mode. Improve efficiency.
>> ;===================================================================
>> setfileoption(fout,"DefineMode",True)
>>
>> ;===================================================================
>> ; create global attributes of the file
>> ;===================================================================
>> fAtt = True ; assign file attributes
>> fAtt@title = "NCL Efficient Approach to netCDF Creation"
>> fAtt@source_file = "original-file.nc"
>> fAtt@Conventions = "None"
>> fAtt@creation_date = systemfunc ("date")
>> fileattdef( fout, fAtt ) ; copy file attributes
>> ;===================================================================
>> ; predefine the coordinate variables and their dimensionality
>> ; note: to get an UNLIMITED record dimension, we set the dimensionality
>> ; to -1 and set the unlimited array to True.
>> ;===================================================================
>> dimNames = (/"lat", "lon"/)
>> dimSizes = (/nlat, nlon/)
>> dimUnlim = (/False, False/)
>> filedimdef(fout, dimNames, dimSizes, dimUnlim)
>>
>>
>>
>> filevardef(fout, "lat" ,typeof(lat), "lat")
>> filevardef(fout, "lon" ,typeof(lon), "lon")
>> filevardef(fout, "FC", typeof(dummy_data), (/"lat" ,"lon"/))
>>
>>
>> filevarattdef(fout, "lat", lat) ; copy lat attributes
>> filevarattdef(fout, "lon", lon) ; copy lon attributes
>> filevarattdef(fout, "FC", dummy_data) ; copy TOPOG attributes
>>
>> setfileoption(fout, "DefineMode", False)
>>
>>
>> fout->lat = (/lat/)
>> fout->lon = (/lon/)
>> fout->FC = (/dummy_data/)
>>
>>
>> delete(dummy_data)
>> delete(fout)
>>
>> end do
>>
>>
>> end
>>
>>
>> Regards
>>
>>
>>
>>
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>
> <XCut_025_FLFC_01_213K.txt><XCut_025_FLFC_02_213K.txt><XCut_025_FLFC_03_213K.txt><XCut_025_FLFC_04_213K.txt>

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Received on Wed Nov 23 12:13:33 2011