[ncl-talk] convert_to_netcdf
Kunal Bali
kunal.bali9 at gmail.com
Wed Nov 22 12:19:53 MST 2017
Sir,
Actually, these numbers are the conversion factor values (for converting
AOD to PM2.5) and I have to multiply these values with .nc files (having
AOD variable) which have been converted from hdf files with the help of
yours as well. After multiplication I will get the values of PM2.5.
Therefore, I want to convert .asc file into .netcdf. With the same data
file format (.nc ), that would be easy then (i guess).
So, this .asc file having conversion factor numbers are distributed all
over Indian region from 5 to 91.33 with the resolution 0.1
The problem is that .nc is 1km (0.01) and this .asc file is10 km (0.1)
resolution. So, I thought If I am able to convert .asc file into netcdf
then I will do the regridding this file via CDO and then multiply both the
files in NCL. So that I will get resultant PM2.5 values.
Also .nc file is curvilinear grid structure and in patches. And this .asc
file covers the whole Indian region. So the multiplication of these two
files would be fine?
regards
Kunal Bali
On Wed, Nov 22, 2017 at 11:47 PM, Dennis Shea <shea at ucar.edu> wrote:
> How closely did you look at your ascii data file?
>
> Did you look at the values?
>
> Really, How is anybody going to determine what you are doing? It is just a
> bunch of numbers. Here is a start for *you*
>
> === data file
> ncols 241
> nrows 291
> xllcenter 91.33
> yllcenter 5.00
> cellsize 0.1
> NODATA_value -999
> 133.0 136.0 138.0 .....
>
> ===
>
> data = asciiread("/home/kunal/20040101.asc", -1,"float")
> nData= dimsizes(data)
> printVarSummary(data)
> print("nData="+nData)
> print("---")
>
> nCols = toint(data(0)) ; ncols
> nRows= toint(data(1)) ; nrows
> nPts = nCols*nRows
> print("nCols="+nCols+" nRows="+nRows+" nPts="+nPts)
> print("---")
>
> xllcenter = data(2)
> yllcenter = data(3)
> cellsize = data(4)
> data at _FillValue = data(5)
> values = data(6:) ; lat and lon mixed????
> print(values)
> printMinMax(values,0)
>
> On Tue, Nov 21, 2017 at 10:55 PM, Kunal Bali <kunal.bali9 at gmail.com>
> wrote:
>
>> I tried to convert ascii format (attached previous mail) to netcdf by the
>> script given below.
>> The script is generating the netcdf file but the lat lon dimensions did
>> not correctly assign.
>>
>>
>> please let me know how to correct this script.
>>
>>
>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/shea_util.ncl"
>> load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
>>
>> begin
>>
>> nLatitude = 241
>> nLongitude = 291
>>
>> data = asciiread("/Users/Pushp/Desktop/COD_NEW/PM2.5/in.txt",(/
>> nLatitude*nLongitude/),"float")
>> printVarSummary(data)
>>
>> Latitude = data(:nLatitude-1)
>> Longitude = data(:nLongitude-1)
>> printVarSummary(Latitude )
>> printVarSummary(Longitude)
>>
>> CF = data(:)
>> CF2D = onedtond(CF,(/nLatitude,nLongitude/))
>>
>> printVarSummary(CF2D)
>>
>> if (any(isnan_ieee(CF2D))) then
>> value = 1.e20
>> replace_ieeenan (CF2D, value, 0)
>> CF2D at _FillValue = value
>> end if
>>
>> ; printMinMax(Latitude,0)
>> ; printMinMax(Longitude,0)
>> printMinMax(CF2D,0)
>>
>> ; Assign named dimensions
>>
>> CF2D!0 = "lat"
>> CF2D!1 = "lon"
>>
>> ; Assign coordinate variables
>>
>> CF2D&lat = Latitude
>> CF2D&lon = Longitude
>>
>> CF2D&lat at units = "degrees_north"
>> CF2D&lon at units = "degrees_east"
>>
>> printVarSummary(CF)
>> ; delete existing netcdf file to create a new one
>> system("rm -rf test.nc")
>> ncdf = addfile("/Users/Pushp/Desktop/COD_NEW/PM2.5/test.nc","c")
>>
>> ; write data to netcdf file
>>
>> ncdf->CF = CF2D
>>
>> end
>>
>>
>>
>>
>>
>> regards
>> Kunal Bali
>>
>>
>>
>>
>>
>>
>> On Tue, Nov 21, 2017 at 6:29 PM, Kunal Bali <kunal.bali9 at gmail.com>
>> wrote:
>>
>>> I tried to convert ascii to netcdf with the attached script, but not
>>> able to get the result.
>>>
>>>
>>> regards
>>> Kunal Bali
>>>
>>>
>>>
>>>
>>>
>>> On Mon, Nov 20, 2017 at 9:47 PM, Douglas Lowe <
>>> Douglas.Lowe at manchester.ac.uk> wrote:
>>>
>>>> Dear Kunal Bali,
>>>>
>>>> It is definitely possible - the UK nation emissions data is provided in
>>>> a similar csv text format to the file you attached, and I have previously
>>>> converted this to netcdf format using NCL.
>>>>
>>>> You need to use the readAsciiHead function to read the header, and then
>>>> the readAsciiTable function to read the table (using the parameters that
>>>> you have gained from reading the header information). Once you have the
>>>> data in a 2D array then it can be written into a netcdf file, after you've
>>>> defined the file.
>>>>
>>>> My scripts wont be directly applicable to your task (as they also
>>>> conversion of BNG coordinates to longitude & latitude coordinates), but if
>>>> you would like to use them as a template to guide you in writing your
>>>> scripts then email me, and I'd be happy to send you a copy.
>>>>
>>>> Regards,
>>>> Doug
>>>>
>>>> ----------------------------------------------------------------------
>>>>
>>>> Message: 1
>>>> Date: Mon, 20 Nov 2017 21:13:08 +0530
>>>> From: Kunal Bali <kunal.bali9 at gmail.com>
>>>> To: "ncl-talk at ucar.edu" <ncl-talk at ucar.edu>
>>>> Subject: [ncl-talk] convert_to_netcdf
>>>> Message-ID:
>>>> <CAOiHCtRKsHCjTnje+28ntzjMObLiVt5j9U5Xst3DUrVQDjyWQg at mail.gm
>>>> ail.com>
>>>> Content-Type: text/plain; charset="utf-8"
>>>>
>>>> Dear NCL users,
>>>>
>>>> Is it possible to convert attached .asc file format to netcdf? It seems
>>>> like CDL format?
>>>>
>>>> Could anyone please let me know that?
>>>>
>>>>
>>>> regards
>>>> Kunal Bali
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>>>> -------------- next part --------------
>>>> ncols 241
>>>> nrows 291
>>>> xllcenter 91.33
>>>> yllcenter 5.00
>>>> cellsize 0.1
>>>> NODATA_value -999
>>>> 133.0 136.0 138.0 141.0 144.0 147.0 150.0 152.0 155.0 157.0 159.0 162.0
>>>> 164.0 167.0 159.0 147.0 135.0 123.0 111.0 98.0 86.0 84.0 81.0 79.0 76.0
>>>> 74.0 71.0 70.0 70.0 70.0 71.0 71.0 72.0 72.0 84.0 101.0 118.0 134.0 151.0
>>>> 168.0 185.0 197.0 209.0 222.0 234.0 246.0 258.0 266.0 266.0 266.0 266.0
>>>> 265.0 265.0 265.0 254.0 237.0 221.0 204.0 188.0 171.0 155.0 156.0 158.0
>>>> 160.0 161.0 163.0 164.0 165.0 162.0 159.0 156.0 153.0 150.0 147.0 144.0
>>>> 140.0 137.0 133.0 130.0 126.0 123.0 120.0 117.0 114.0 111.0 ......
>>>> ------------------------------
>>>>
>>>> Subject: Digest Footer
>>>>
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>>>> ------------------------------
>>>>
>>>> End of ncl-talk Digest, Vol 168, Issue 44
>>>> *****************************************
>>>>
>>>
>>>
>>
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