============================================
Nagg version 1.6.0 released on 2014-01-31.
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1. Introduction
===============

This document describes the NPP Aggregation tool, nagg, and contains
information on platforms tested, changes since last release and any known
problems.

If you have any questions or comments, please send them to:
    help@hdfgroup.org


2. Platforms Tested
===================
Linux 2.6 32bit and 64bit with gcc 4.1.2, gcc 4.4.7 and icc 13.1.3


3. New features and bug fixes since Version 1.5.1
=================================================
    Configuration
    -------------
    - None
    
    Features
    --------
    - Nagg command options have been added to apply storage layout changes 
      and compression filters to datasets in the /All_Data group while 
      aggregating or packaging NPP product granules. Compression filters 
      that can be used include HDF5 built-in filters such as shuffle, GZIP, 
      and SZIP. Specifying --filter=NONE will remove any existing filter. 
      nagg can also use HDF5's recently introduced dynamically loaded user 
      defined filters. Dynamically loaded filters must be available for 
      later access to the data compressed with them.  For more information, 
      see the nagg --help message or the nagg documentation.
    - All filters require CHUNKED layout, which is standard for NPP datasets.
      Changing the layout to COMPACT or CONTIGUOUS will remove any existing 
      filter, is incompatible with all filters, and will remove any existing
      filters for the dataset.  
    - Beginning with this version nagg will write user block attributes 
      according to the JPSS Common Data Format Control Book specification.  
      The user block can be viewed  using a text editor (or "head -n1 <file>" 
      on unix systems) without the HDF5 library. Saving the userblock text to 
      an XML file and opening it in a web browser will display it as an XML 
      document tree.

    Bug Fixes
    ---------
    - JPSS-62 nagg output files do not have user block information.  The user 
      block has been added in version 1.6.0.
    - JPSS-85 nagg should detect --filter and --layout conflicts and return an
      error before processing files.  Previously these conflicts were not
      detected until the new dataset was created, after all granules in the 
      input files were read.  The conflicts are now detected when parsing
      the command line entries.

    Limits
    ------
    - See nagg.docx (html, pdf) in the same directory for proposed functionality.
    Current release has the following limitations: 
       * Like (--like) option retrieves three properties (number of granules,
         types contained, and geolocation product or external geolocation file
         attribute) from the example file.  Whether the output should be
         packaged or unpackaged is determined from the geolocation
         characteristics of the example file.  Geolocation only aggregation
         is now supported, but origin and domain are determined only from the
         command line options. 
       * Environment variables or command line options for compliance 
         with file naming convention presume valid types and packaging as
	 defined in the "nagg.h" file.
       * Warnings or failures if granule gaps exceed some threshold are not
         supported.
       * Options to choose repair granule are not supported; for now, the one
         with the latest version is used.
       * Option to replace existing granule with repair granule is not
         supported.  
       * Restrictions on flags and input parameters:
            Directory input is not supported.

      
4. Known problems
=================

    - nagg copies the value of the BeginningOrbitNumber attribute from the
      first granule in an aggregation and the value of the EndingOrbitNumber
      attribute to the attributes in the ..._Aggr dataset for the aggregation.
      If either of those granules are fill granules the value of these 
      attributes may be 0 or a fill value.
    - nagg may fail with a segmentation fault if there is insufficient disk
      drive space to hold the output files.  In general the ouput files will 
      require the same amount of disk space as the input files.