Re: Reading TRMM data

From: Dennis Shea <shea_at_nyahnyahspammersnyahnyah>
Date: Wed May 23 2012 - 12:32:58 MDT

The script hdf4sds_1.ncl reads a hdf file not a binary file.

NCL can read any binary file but files with mixed variable types
[character, byte (integer*1) and short (integer*2)]
are a nuisance read.

You can look at the header file using (say) 'less' or 'more'

%> less 3B42RT.2012010100.6.bin

algorithm_ID=3B42RT algorithm_version=02.00
granule_ID=3B42RT.2012010100.6.bin header_byte_length=2880
file_byte_length=(char2880)_header+(int2)x1440x720x2_data+(int1)x1440x720_data+(int2)x1440x720_data
nominal_YYYYMMDD=20120101 nominal_HHMMSS=000000 begin_YYYYMMDD=20111231
begin_HHMMSS=223000 end_YYYYMMDD=20120101 end_HHMMSS=013000
creation_date=20120101 west_boundary=0E east_boundary=360E
north_boundary=60N south_boundary=60S origin=northwest
number_of_latitude_bins=480 number_of_longitude_bins=1440
grid=0.25x0.25_deg_lat/lon first_box_center=59.875N,0.125E
second_box_center=59.875N,0.375E last_box_center=59.875S,359.875E
number_of_variables=4
variable_name=precipitation,precipitation_error,source,uncal_precipitation
variable_units=mm/hr,mm/hr,source_number,mm/hr
variable_scale=100,100,1,100
variable_type=signed_integer2,signed_integer2,signed_integer1,signed_integer2
byte_order=big_endian flag_value=-31999
flag_name=insufficient_observations contact_name=TSDIS_Helpdesk
contact_address=NASA/GSFC_Code_610.2_Greenbelt_MD_20771_USA
contact_telephone=301-614-5184 contact_facsimile=301-614-5575
contact_email=helpdesk@pps-mail.nascom.nasa.gov run_latency=LAST

Please look at this in detail. It looks like it has conflicting
information (eg grid size 720 and 480). It is *your* job to
understand the correct settings.

ncl-talk people do not have the time to look at the file
or to validate.

Attached is a script that reads, plots and create netCDF.
It is a variation of hdf4sds_1.ncl

On 5/21/12 9:32 AM, Mary Haley wrote:
> See example "hdf4sds_1.ncl" at:
>
> http://www.ncl.ucar.edu/Applications/HDF.shtml
>
> --Mary
>
> On May 20, 2012, at 6:13 AM, ousmane ndiaye wrote:
>
>> hi,
>> I want to read and plot the TRMM data does any one know how to do that.
>> 3B42RT.2012010100.6.bin.gz
>> Ousmane
>>
>>
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Received on Wed May 23 12:33:11 2012

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