GRS Code

See:
Description

Packages

grs.pds
grs.pds.ahd
grs.pds.and
grs.pds.cgs
grs.pds.dhd
grs.pds.dnd
grs.pds.edr
grs.pds.sgs
grs.spice

GRS Code

Description

Describes how to obtain and use the GRS code, a library of Java^TM classes (with source code) that may be used to parse the data files in GRS EDR, CGS, DND, and SGS records.

Requirements

A Java 2 Runtime Environment (JRE) of version 1.3 or higher is required to use the EDR code. A JRE may be obtained from Sun Microsystems, Inc., or from other vendors.

Where To Obtain the GRS Code

The GRS code is distributed with the GRS PDS Archives available from NASA's Planetary Data System. Source code and binary classes are located within a Java Archive (JAR) named grs_code.zip in the software directory. To extract source code from the jar, use a unzip utility or the jar utility distributed with a Java 2 Software Development Kit (SDK).

Using the GRS Code

The GRS code is designed to be used as a software library. In other words, it exposes an API (Application Programming Interface) that may be used by developers to build applications that parse and extract information from data files.

Alternately, the source code my be used as a guide to designing applications in other languages that parse GRS data files.

How To Parse GRS Records

For each type of record file in a GRS PDS archive, there is a corresponding class. The following table lists the correspondence:

Classes to use for each record type.

Record Type	Class File
CORRECTED_GAMMA_SPECTRA	grs.pds.cgs.CorrectedGammaSpectraRecord
DERIVED_NEUTRON_DATA	grs.pds.dnd.NsDerivedRecord
GAMMA_SPECTRA	grs.pds.edr.GammaEdrRecord
NEUTRON_SPECTRA	grs.pds.edr.NsEdrRecord
HEND_SPECTRA	grs.pds.edr.HendEdrRecord
PULSER_SPECTRA	grs.pds.edr.PulserEdrRecord
PROFILE_DATA	grs.pds.edr.ProfileEdrRecord
COMMAND_LIST	grs.pds.edr.CmdEdrRecord
MESSAGE_LOG	grs.pds.edr.MsgEdrRecord
ENG_DATA	grs.pds.edr.EngEdrRecord
CHAN_DATA	grs.pds.edr.ChanEdrRecord
E_KERNEL_NOTES	grs.pds.edr.EkEdrRecord
E_KERNEL_PEF	grs.pds.edr.PefEdrRecord
SUMMED_GAMMA_SPECTRA	grs.pds.sgs.SummedGammaSpectraRecord

Each class includes a java.io.DataInputStream constructor. So, the basic usage would be to:

1. Open a DataInputStream to a file
2. While the file has more records:
   • Create a new object of the appropriate class by passing the reference to the DataInputStream to the constructor
   • Record values are now available through instance member fields of the object
3. Close the DataInputStream

Each class also includes a main method that demonstrates this basic usage.

Sample Application

A sample application is provided that converts EDR, CGS, or SGS files to Comma-Seperated Value (CSV) files.

Usage: java -jar grs_code.zip <path-to-data-file>

Please note that it does not include all columns in the output. In particular, the spectra data are not output to CSV. To access this data, please use the API as described above.