[ncl-talk] Data conversion

Fri Feb 5 06:57:07 MST 2016

Goodday sir,
I appreciate your effort in guiding me. I'm new in this platform, please
dont be offended by sending the message three times, I'm just learning to
get help from here.
I used the script,
begin
file_name_read = "merg_2012090101_4km-pixel"

ir_u = byte2flt( fbindirread (file_name_read ,0, (/2,3298,9896/),"ubyte"))
+75.0

lon_g = fspan(0.0182,360,9896)
lat_g = fspan(59.982,59.982-0.036383683*3298,3298)

lon_g at units      = "degrees_east"
lon_g at long_name  = "longitude"
lon_g at short_name = "longitude"
lon_g!0 = "lon"
lon_g&lon = lon_g

lat_g at units      = "degrees_north"
lat_g at long_name  = "latitude"
lat_g at short_name = "latitude"
lat_g!0 = "lat"
lat_g&lat = lat_g

ir_u!0      = "time"
ir_u!1      = "lat"
ir_u!2      = "lon"

ir_u&lat    = lat_g
ir_u&lon    = lon_g

ir_u at _FillValue= 255+75.0

wks = gsn_open_wks("X11","")
res = True
res at cnFillOn = True
res at cnFillMode = "RasterFill"
res at cnLinesOn = False
plot = gsn_csm_contour_map(wks, ir_u(0,:,:), res)

ncout = addfile(file_name_read+".nc","c")
ncout->ir_data = ir_u

end

But it was generating this error:
fatal:Undefined identifier: (byte2flt) is undefined, can't continue
fatal:["Execute.c":7741]:Execute: Error occurred at or near line 41

Waiting for guide, Thanks.

On Thu, Feb 4, 2016 at 8:07 PM, Alan Brammer <abrammer at albany.edu> wrote:

> Forgot the offset, which is mentioned in the link Kevin sent.
>
>
> ir_u = byte2flt( fbindirread (file_name_read ,0, (/2,3298,9896/),"ubyte"))*
> +75.*
> ir_u at _FillValue= 255*+75.*
>
> "Each record is a 9896 x 3298 Fortran array of IR brightness temperatures
> that have been scaled to fit into 1-byte by subtracting "75" from each
> datum. Therefore it is necessary for the user to add a value of "75" to
> each data value when using the data."
>
>
> On 4 Feb 2016, at 13:30, Alan Brammer <abrammer at albany.edu> wrote:
>
> ok, wow. Don’t send the same message 3 times, if the first answers weren’t
> complete at least expand and attempt something not just copy paste the same
> lines again.
>
> as said before .Z means it’s compressed.
>  gunzip merg_2016020123_4km-pixel.Z  will uncompress it. Then you have a
> binary file as a small amount of googling would have told you.
> The same search would have linked you to various messages on here and
> various scripts where other people have included simple examples of this
> file type (myself included). Here is an example of reading and making a
> simple plot.  There are plenty of examples on how to write netcdf on the
> NCL website so you should develop code from there.  Most simple example at
> bottom of script below.
> https://www.ncl.ucar.edu/Applications/o-netcdf.shtml
>
> Read the documentation on the below functions and understand what is
> occurring .
>
>
> begin
> file_name_read = "merg_2016020123_4km-pixel"
>
> ir_u = byte2flt( fbindirread (file_name_read ,0, (/2,3298,9896/),"ubyte"))
>
>
> lon_g = fspan(0.0182,360,9896)
> lat_g = fspan(59.982,59.982-0.036383683*3298,3298)
>
> lon_g at units      = "degrees_east"
> lon_g at long_name  = "longitude"
> lon_g at short_name = "longitude"
> lon_g!0 = "lon"
> lon_g&lon = lon_g
>
> lat_g at units      = "degrees_north"
> lat_g at long_name  = "latitude"
> lat_g at short_name = "latitude"
> lat_g!0 = "lat"
> lat_g&lat = lat_g
>
>
> ir_u!0      = "time"
> ir_u!1      = "lat"
> ir_u!2      = "lon"
>
> ir_u&lat    = lat_g
> ir_u&lon    = lon_g
>
> ir_u at _FillValue= 255
>
>
> wks = gsn_open_wks("X11","")
> res = True
> res at cnFillOn = True
> res at cnFillMode = "RasterFill"
> res at cnLinesOn = False
> plot = gsn_csm_contour_map(wks, ir_u(0,:,:), res)
>
> ncout = addfile(file_name_read+”.nc”,”c”)
> ncout->ir_data = ir_u
>
> end
>
>
>
>
>
> On 4 Feb 2016, at 13:04, Benjamin Alabi <alabibenjamin2 at gmail.com> wrote:
>
> Thanks for your assistance sir. I've tried the cdo to get general
> information on the data, but it didn't work
> I need help from someone that can guide me to convert this data format -
> 'merg_2012091000_4km-pixel.Z' to netcdf format.
> I download Gobally-merged (60N-60S) pixel-resolution IR brightness
> temperature data (equivalent blackbody temps), merged from all available
> geostationary satellites (GOES-8/10, METEOSAT-7/5)
> This is the link:
>
> http://mirador.gsfc.nasa.gov/cgi-bin/mirador/presentNavigation.pl?tree=project&dataset=Global-merged%20IR%20Brightness%20Temperature%20Data&project=TRMM&dataGroup=Ancillary&version=001&CGISESSID=25c6337b80163b3743e8bea85d015558
> .
> I really want it to be in netcdf format.
>
> Regard
>
>
>
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>
>
>
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