Re: reading HDF file and SDS attributes in NCL?

From: Sylvia Murphy (murphys AT XXXXXX)
Date: Mon Sep 29 2003 - 11:05:45 MDT

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    Louis, to access an attribute in ncl, you need to use the @ sign. the &
    sign you used is for the coordinate variables:

    e.g. print(x@long_name)

    or print(x&lat)

    sm

    On Mon, 29 Sep 2003, Louis Wicker wrote:

    > All:
    >
    > for various reasons, I need to use HDF4 for writing out some cloud model
    > data. I am using some data compression in HDF4, and need to store off
    > some information for the compression.
    >
    > I realize I can do this in another way, but I was hoping that NCL could
    > access either some file attributes and more importantly, the attributes
    > of the HDF SDS's.
    >
    > Interestingly, when I write an SDS with attributes, NCL seems to know
    > they are there, but I cannot see how to get at them - see example below:
    >
    > m5:/home/wicker/SRC/NCL/hdftest 31# ncl
    > Copyright (C) 1995-2002 - All Rights Reserved
    > University Corporation for Atmospheric Research
    > NCAR Command Language Version 4.2.0.a026
    > The use of this software is governed by a License Agreement.
    > See http://ngwww.ucar.edu/ncl/ for more details.
    > ncl 0> fil = addfile("SDS.hdf", "r")
    > ncl 1> data = fil->SDStemplate
    > ncl 2> printVarSummary(data)
    >
    >
    > Variable: data
    > Type: short
    > Total Size: 20000 bytes
    > 10000 values
    > Number of Dimensions: 2
    > Dimensions and sizes: [Y_Axis | 100] x [X_Axis | 100]
    > Coordinates:
    > Y_Axis: [ 0..9.900000147521496]
    > X_Axis: [0..99]
    > Number Of Attributes: 1
    > Valid_range : <ARRAY>
    > ncl 3> print(data&Valid_range)
    > fatal:(Valid_range) is not a named dimension in variable (data).
    > fatal:Execute: Error occurred at or near line 3
    >
    > Is there a way to reference the information stored in the Attributes?
    >
    > Thanks.
    >
    > Lou Wicker
    >

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